| 单词 | Silurian |
| 例句 | Most of these are also reasonably well known: Cretaceous, Jurassic, Triassic, Silurian, and so on.* A Short History of Nearly Everything 2003-05-06T00:00:00Z Famously, in the Third Doctor Silurian story, the Brigadier orders the destruction of the underground Homo Repltilia settlement, to the Doctor's disgust. Nicholas Courtney, Doctor Who's legendary Brigadier, mourned by fans 2011-02-23T14:25:48Z It was mentioned last week that the updated Silurians are human-faced rubber monsters more at home in Star Trek. Doctor Who: Cold Blood - series 31, episode nine 2010-05-29T18:50:00Z We watched in stunned horror as Rory was shot by a Silurian and absorbed by time energy; his entire existence erased from history. What's the crack? 2010-06-18T13:07:00Z He writes for Styles and is a three-time winner of the New York Press Club award for city writing and a three-time winner of Silurians Press Club medallions for his feature writing. The Life and Death of a ‘Punk Rock Warhol’ 2023-07-27T04:00:00Z Your enjoyment of Cold Blood would seem to hinge entirely on whether you've seen a Silurian story before. Doctor Who: Cold Blood - series 31, episode nine 2010-05-29T18:50:00Z Although the idea of sentient, technological reptiles immediately reminds us of Star Trek’s Gorns or Doctor Who’s Silurians, there has actually been a scientific debate about this possibility for more than four decades. How Smart Were Dinosaurs? New Studies Fuel the Debate 2023-07-06T04:00:00Z The first type of leaf is the microphyll, or “little leaf,” which can be dated to 350 million years ago in the late Silurian. Fundamentals of Biology 2015-01-01T00:00:00Z This fact is used as evidence that nonvascular plants must have preceded the Silurian period. Concepts of Biology 2013-04-25T00:00:00Z By the end of the Silurian, jawed fishes began to appear; the advantage of jaws is that it makes for better hunters, which allowed such fish to better pass down their genes. How a Chinese fish fossil discovery rewrites the history of life's evolution 2022-10-01T04:00:00Z But until recently, the number of useful Silurian gnathostome fossils could be counted on one hand. Fossilized Fish Reveal Earliest Known Prequel of ‘Jaws’ 2022-09-28T04:00:00Z The fossils date back to the Silurian period, an important era for life on earth from 443 million years ago to 419 million years ago. Fish fossil catch from China includes oldest teeth ever 2022-09-28T04:00:00Z It starts with the Cambrian period, followed by the Ordovician, Silurian, Devonian, Carboniferous, and Permian. Fundamentals of Biology 2015-01-01T00:00:00Z It was at this time, for example, that the trilobites, a group that survived the Ordovician–Silurian extinction, became extinct. Biology for AP Courses 2022-06-09T00:00:00Z The largest salt mine in the world is at Goderich, Ontario, where salt is recovered from the 100 m thick Silurian Salina Formation. Physical Geology 2015-01-01T00:00:00Z The presence of shark relatives at the site suggests that the split between cartilaginous and bony fish had already occurred by the early Silurian, Dr. Friedman said. Fossilized Fish Reveal Earliest Known Prequel of ‘Jaws’ 2022-09-28T04:00:00Z The first bony fish and shark are also Silurian, which includes the first primitive jaws. An Introduction to Geology 2017-01-01T00:00:00Z This compelling fact is used as evidence that non-vascular plants must have preceded the Silurian period. Fundamentals of Biology 2015-01-01T00:00:00Z In 1970 he played Masters in Doctor Who and the Silurians. Obituary: Geoffrey Palmer 2020-11-06T05:00:00Z Researchers said the fossil of the Silurian Period creature, called Kampecaris obanensis and unearthed on the island of Kerrera in the Scottish Inner Hebrides, inhabited a lakeside environment and likely ate decomposing plants. Millipede from Scotland is world's oldest-known land animal 2020-05-30T04:00:00Z As paleontologists continue to dig deeper into early Silurian rocks in China, they’ve uncovered even more fish species. Fossilized Fish Reveal Earliest Known Prequel of ‘Jaws’ 2022-09-28T04:00:00Z Reptilian menaces called Silurians evolved on Earth before humankind — at least in the “Doctor Who” rendition of the universe. Could intelligent life have existed on Earth millions of years before humans? 2018-04-20T04:00:00Z That 1970 episode of the classic TV series involves the present-day discovery of “Silurians”—an ancient race of technologically advanced, reptilian humanoids who predated the arrival of humans by hundreds of millions of years. Could an Industrial Prehuman Civilization Have Existed on Earth Before Ours? 2018-04-23T04:00:00Z The agency scaled the regulations back to 15 eastern counties with Silurian bedrock under their soil. DNR board set to adopt CAFO manure restrictions 2018-01-23T05:00:00Z The researchers examined fossils of two primitive bony fish from the Silurian Period, a time of evolutionary advances in marine life, and found an enamel coating on their scales but no enamel on their teeth. Fish scales to fangs: Surprising tale of how teeth got their bite 2015-09-23T04:00:00Z About 420 million years ago, near the end of the so-called Silurian period, the last of a series of mass extinctions struck the world’s oceans. Death metal in ancient oceans 2015-08-25T04:00:00Z The surveys are conducted from the research vessel, Silurian. Rise in basking shark sightings 2013-12-20T00:20:55Z Schmidt and Frank paid tribute to the episode in the title of their paper: “The Silurian Hypothesis.” Could an Industrial Prehuman Civilization Have Existed on Earth Before Ours? 2018-04-23T04:00:00Z It is believed the fort was once a stronghold of the powerful Silurian tribe who inhabited this part of Wales before the arrival of the Romans. City suburb dig for Iron Age fort 2013-06-24T08:54:39Z Her character witnessed the reawakening of an ancient race in The Silurians and stopped an insane scientist from cracking open the Earth's crust in Inferno. Doctor Who actress John dies, 72 2012-06-21T11:50:33Z If this being so simple existed at the epoch which geologists term the Silurian period, it is many millions of ages past. The Catholic World; Volume I, Issues 1-6 A Monthly Eclectic Magazine 2012-04-05T02:00:40.207Z It is believed that insects of this group are represented among Silurian fossils. Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 4 "Hero" to "Hindu Chronology" 2012-04-04T02:00:56.447Z “Of course, no matter what, this is going to be interpreted as ‘Astronomers Say Silurians Might Have Existed,’ even though the premise of this work is that there is no such evidence,” he says. Could an Industrial Prehuman Civilization Have Existed on Earth Before Ours? 2018-04-23T04:00:00Z The age of Invertebrates, or the Silurian, when the life on the globe consisted distinctively of invertebrates. Webster's Unabridged Dictionary 2012-03-24T02:00:23.513Z Write—with a three-and-nine-penny fountain pen, on Silurian notepaper at a shilling a packet? A Knight on Wheels 2011-12-24T03:08:07.830Z Granite prevails, but at Polperro we have cliffs belonging to the Lower Devonian period, and for some ten or twelve miles going west from Chapel Point we find rocks of the Silurian order. Climbing in The British Isles. Vol. 1 - England 2011-11-14T03:00:21.670Z With his keen eye for fossils he detected organic remains in the Morte slates, previously regarded as unfossiliferous, and these he regarded as including representatives of Lower Devonian and Silurian. Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 4 "Hero" to "Hindu Chronology" 2012-04-04T02:00:56.447Z In this article he also advocated the freshwater origin of the Old Red Sandstone, and discussed the relations of that formation, and of the Devonian, to the Silurian and Carboniferous. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 2 "Gloss" to "Gordon, Charles George" 2011-10-31T02:00:28.703Z The earliest period in geological period, extending up to the Lower Silurian. Webster's Unabridged Dictionary 2012-03-24T02:00:23.513Z Or there might be glaciation in high latitudes, such as that of southern Alaska in the Middle Silurian, and none elsewhere. Climatic Changes Their Nature and Causes 2011-10-28T02:00:24.840Z Along the shores of the Silurian seas they stood up, straight and tall, their only companions that stood erect, the giant horse-tails and tree ferns. Trees Worth Knowing 2011-10-13T02:00:48.357Z Subsequently Hicks contributed a series of important papers on the Cambrian and Lower Silurian rocks, and figured and described many new species of fossils. Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 4 "Hero" to "Hindu Chronology" 2012-04-04T02:00:56.447Z Like the former they occur in low flat beds, sometimes rising into cliffs, but never reaching the elevation attained by the Silurian rocks in Lancaster Sound. In the Arctic Seas A Narrative of the Discovery of the Fate of Sir John Franklin and his Companions 2011-10-10T02:00:18.377Z The Silurian beds form considerable precipices upon the north, almost enclosing numerous tarns, from which interesting ascents may be made. Climbing in The British Isles, Vol. II Wales and Ireland 2011-09-23T02:00:23.653Z This is especially true for Ordovician, Silurian, Devonian, and Jurassic times in North America. Climatic Changes Their Nature and Causes 2011-10-28T02:00:24.840Z Cambrian, Silurian, Devonian, Permian, Jurassic are of this class, and have been adopted all over the globe. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z Several Silurian fossils have been identified as insects, including a Thysanuran from North America, but upon these considerable doubt has been cast. Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 4 "Hero" to "Hindu Chronology" 2012-04-04T02:00:56.447Z A low, sandy beach marks the termination of the valley northwards, and on this beach were found numerous pebbles, washed from the hills of the interior, composed of quartzose sandstone, carnelian, and Silurian limestone. In the Arctic Seas A Narrative of the Discovery of the Fate of Sir John Franklin and his Companions 2011-10-10T02:00:18.377Z Composed of Silurian slates chiefly, it forms an extensive tableland at the north of Killary Fiord, in the south-west corner of Mayo. Climbing in The British Isles, Vol. II Wales and Ireland 2011-09-23T02:00:23.653Z Genus includes several hundred extinct species ranging from the Silurian to the Tertiary. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 5 "Gassendi, Pierre" to "Geocentric" 2011-09-02T02:00:20.450Z In the Silurian system, for example, the graptolites have been shown by C. Lapworth to furnish a useful basis for zonal subdivisions. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z Here, however, for several reasons, we propose to follow Sedgwick's arrangement; and hence, under the term Silurian, retain only Murchison's Upper beds. Sea-Weeds, Shells and Fossils 2011-08-20T02:00:11.557Z The Silurian rocks of the Arctic Archipelago rest everywhere directly on the granitoid rocks, with a remarkable red sandstone, passing into coarse grit, for their base. In the Arctic Seas A Narrative of the Discovery of the Fate of Sir John Franklin and his Companions 2011-10-10T02:00:18.377Z Fig. 3.—Section obtained by boring with the diamond drill, near Goderich, Ontario, Canada, in the Salina series of the Upper Silurian. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z Sir R. J. Murchison says, "there are no traces of land plants in the great mass of the Silurian rocks." The Bible: what it is 2011-05-31T02:00:29.687Z He at first believed, as Murchison also did, that his rocks were all older than any part of the Silurian series. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z In the Silurian system in New York, Ontario, Michigan, etc., several beds of rock salt and gypsum occur, indicating that there were formerly a number of separate evaporating basins in that region. North America 2011-05-05T02:00:20.027Z This resemblance to the Upper Silurian beds extends to the structure of the rocks on the large scale. In the Arctic Seas A Narrative of the Discovery of the Fate of Sir John Franklin and his Companions 2011-10-10T02:00:18.377Z This may be seen in Fig. 9, which represents a magnified slice of a Silurian limestone. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z The first sign of animal life yet discovered is of the radiate class, in the lowest zone of the lower Silurian. The Bible: what it is 2011-05-31T02:00:29.687Z It is only when we pass into the Silurian Wenlock limestone that sandy shells make their appearance. Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 6 "Foraminifera" to "Fox, Edward" 2011-04-22T02:00:08.637Z This "Appalachian peninsula" would be conspicuous in a map representing the outline of the continent at the close of the Silurian. North America 2011-05-05T02:00:20.027Z The Upper Silurian limestones already described are succeeded by a most remarkable series of close-grained white sandstones, containing numerous beds of highly bituminous coal, and but few marine fossils. In the Arctic Seas A Narrative of the Discovery of the Fate of Sir John Franklin and his Companions 2011-10-10T02:00:18.377Z These Graptolites are specially characteristic of the Upper Cambrian and Lower Silurian. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z Devo�nian System, in geology, a name originally given to rocks in Devonshire and Cornwall, intermediate between the Silurian and Carboniferous strata, and consisting of sandstones, calcareous slates and limestones, &c. The New Gresham Encyclopedia Volume 4, Part 1: Deposition to Eberswalde 2011-04-14T02:00:57.977Z Are not the beings of the Silurian and Devonian epoch prophecies of the forms which were evolved out of them? Studies in the Out-Lying Fields of Psychic Science 2011-04-14T02:00:40.453Z Next in age after the Laurentian Highlands come the mountains of New England and the maritime province of Canada, which were upraised at the close of the Silurian period. North America 2011-05-05T02:00:20.027Z Silurian strata, mostly of Wenlock age, lie below the carboniferous limestone on the western border of the county. Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 5 "Fleury, Claude" to "Foraker" 2011-04-03T02:00:20.883Z Upwards of three thousand fossil species are known, of which a large proportion belong to the Cambrian and Silurian, nine genera appearing in the Cambrian, and no less than fifty-two in the Silurian. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z It is probable that a great land-mass lay towards the north-west; but in the sea which certainly existed south-east of the chain, the Cambrian, Ordovician and Silurian beds were deposited. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 8 "Ethiopia" to "Evangelical Association" 2011-03-05T03:00:24.537Z It was entirely covered with the bottom moraine of the great ice-sheet of the Glacial Epoch, resting upon Silurian sandstones and limestones. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 7 "Equation" to "Ethics" 2011-02-27T03:00:31.973Z Succeeding the Algonkian system come, in succession, the Cambrian, Ordovician, and Silurian systems. North America 2011-05-05T02:00:20.027Z Devonian, the geological age between the Silurian and Carboniferous. A Manual of the Antiquity of Man 2011-02-21T03:00:07.080Z Figs. 77 and 78 show a few of the forms of the Silurian, Devonian, and Carboniferous. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z It was raised at the close of the Silurian period. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 8 "Ethiopia" to "Evangelical Association" 2011-03-05T03:00:24.537Z In the Old Red Sandstone are numerous fish remains; it appears to have been an estuarine or lacustrine deposit; the Devonian, on the other hand, was marine, like the Silurian and Cambrian. Geology 2011-02-20T03:00:12.660Z At the close of the Silurian there was a decided increase in the size of the main nucleus of the continent. North America 2011-05-05T02:00:20.027Z Fourth edition, Including "The Silurian System," with a map, much new matter, and many illustrations. . . . A Catalogue of Books in English Later than 1700 (Vol 2 of 3) Forming a portion of the library of Robert Hoe 2011-02-16T03:00:34.387Z The supposed fern of the Upper Silurian, figured in the first edition of this work, has proved on further examination to be merely an imitative form produced by crystallisation. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z Cream-laid, with a gold address at the top, bespeaks the early days of matrimony; and a descent through white stamping, no stamping, Hieratica to Silurian note, marks the different stages of the rolling years. A Lame Dog's Diary 2011-02-04T03:00:23.707Z The oldest rocks of Elba consist of schist and serpentine which in the eastern part of the island are overlaid by beds containing Silurian and Devonian fossils. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 2 "Ehud" to "Electroscope" 2011-01-29T03:00:23.777Z Although at the close of the Silurian the continent had greatly increased in area over that of the nucleus at the close of the Archean, it bore but little resemblance to its present form. North America 2011-05-05T02:00:20.027Z All the Silurian strata are repeated by folds striking north-east and south-west and frequently dipping in one direction, to the north-west as in the Gala valley. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 10 "Echinoderma" to "Edward" 2011-01-19T03:00:19.027Z On the other hand, the recent discovery of a cockroach and two species of Scorpion in the Silurian, proves the existence of land animals as well as plants at this period. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z A small patch of Silurian occurs near Cronkley on the Tees; here slate pencils were formerly made. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 8 "Dubner" to "Dyeing" 2010-12-26T03:00:17.840Z Murchison, fresh from the Peninsular campaign, began to study the dawn of organic history in the gloom of the Silurian and Cambrian epochs. Charles Darwin 2010-12-24T03:00:33.847Z Writing for the publication of The Society of the Silurians, an organization of New York journalists, Mr. Ziegel once recalled that his father took a dim view of his obsession with sports. Vic Ziegel, Sportswriter and Editor, Is Dead at 72 2010-07-23T18:05:00Z Geology.—The southern portion of the county, embracing the Moorfoot Hills and a large part of the catchment basin of the Gala Water, lies within the Silurian tableland of the south of Scotland. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 10 "Echinoderma" to "Edward" 2011-01-19T03:00:19.027Z It is probable that these discoveries represent merely a small proportion of the plants actually existing in the Silurian period. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z There is a geological society with a museum, for the neighbourhood of Dudley is full of geological interest, the Silurian limestone abounding in fossils. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 8 "Dubner" to "Dyeing" 2010-12-26T03:00:17.840Z A hummocky irregular country spreads southward, where the Silurian axis is encountered, in continuation of the southern uplands of Scotland. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 5 "Arculf" to "Armour, Philip" Later on he investigated the Carboniferous, Devonian and Silurian formations. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 4 "Aram, Eugene" to "Arcueil" Silurian rocks occupy a large area in South Australia, on both sides of Spencer Gulf. The New Gresham Encyclopedia. Vol. 1 Part 3 Atrebates to Bedlis At any time the discovery of an estuarine or lacustrine deposit of Silurian age might wonderfully extend our knowledge of this ancient flora. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z At the S.E. limit of the Sanquhar Coalfield there are patches of the Carboniferous Limestone series, but towards the N. these are overlapped by the Coal Measures which thus rest directly on the Silurian platform. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 8 "Dubner" to "Dyeing" 2010-12-26T03:00:17.840Z In the western Sierras, which are more or less closely attached to the main chain of the Cordillera, Cambrian and Silurian fossils have been found at several places. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 5 "Arculf" to "Armour, Philip" The Trilobites are known only as fossils, mostly Silurian and prae-Silurian; a few are found in Carboniferous and Permian strata. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 3 "Apollodorus" to "Aral" The mountainous region in the south-east and east is mainly composed of volcanic, Silurian, carbonaceous, and carboniferous rocks yielding good coal. The New Gresham Encyclopedia. Vol. 1 Part 3 Atrebates to Bedlis If they were not, then the earliest known representatives of this class belong to a much later age, that of the Silurian. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z The Upper Old Red Sandstone forms a narrow strip on the south side of the Silurian tableland, resting unconformably on the Silurian rocks and passing upwards into the Carboniferous formation. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 8 "Dubner" to "Dyeing" 2010-12-26T03:00:17.840Z They are followed by another series called the Ordovician; and that by another the Silurian. The Geological Story of the Isle of Wight It is probable that the Silurian scorpion was an aquatic animal, and that its respiratory lamellae were still projecting from the surface of the body to serve as branchiae. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 3 "Apollodorus" to "Aral" In the valley of the Trombetas, one of the northern tributaries of the Amazon, fossils have been found which indicate either the top of the Ordovician or the bottom of the Silurian. Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 4 "Bradford, William" to "Brequigny, Louis" In the Devonian age the Ganoids and Sharks, thus introduced in the Silurian, may be said to culminate. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z In the tract along the Solway Firth they repose on the folded and eroded edges of the Carboniferous strata, and when traced westwards to the Dumfries basin they rest directly on the Silurian platform. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 8 "Dubner" to "Dyeing" 2010-12-26T03:00:17.840Z In the ancient rocks of Wales, the Cambrian and Silurian strata, are thousands of feet of deposits, mostly laid down in fairly shallow water. The Geological Story of the Isle of Wight They became extinct in Palaeozoic times, and are chiefly found in the Upper Silurian, though extending upwards as far as the Carboniferous. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 3 "Apollodorus" to "Aral" Elsewhere the identification of the Silurian and older systems does not rest on palaeontological evidence. Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 4 "Bradford, William" to "Brequigny, Louis" Thickness of beds about 250 feet. a, Boulder clay and gravel—Post-pliocene. b, Niagara limestone c, Niagara shale d, Clinton limestone e, Medina sandstone ┐Upper Silurian, │ with marine shells │ and ┘ corals. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z It is called Silurian, from the name of a kind of fish, fossils of which are found in the rocks of this age, which are distinguished for the absence of land-plant fossils and vertebrate animals. Nature's Miracles, Volume 1 Familiar Talks on Science—World-Building and Life. Earth, Air and Water. At this point we pass on to the axis of underlying Silurian strata that runs from Longford to Donaghadee in Co. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 5 "Cat" to "Celt" In the Thirlmere tunnels, driven through very hard Lower Silurian strata, the progress was about 13 yds. a week at each face, work being carried on continuously day and night for six days a week. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 3 "Apollodorus" to "Aral" The crystalline rocks are succeeded by beds which have been referred to the Cambrian and Silurian systems. Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 4 "Bradford, William" to "Brequigny, Louis" The Lithistids have been recognised in the Upper Silurian and Carboniferous, and continuing upward to the Cretaceous, there become vastly numerous, while their 52modern representatives are by no means few. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z In the Silurian strata are found limestones, slate, flagstones, shales, etc. Nature's Miracles, Volume 1 Familiar Talks on Science—World-Building and Life. Earth, Air and Water. Anthracite, probably of inorganic origin, has been mined without permanent success in the Silurian beds near Kilnaleck, and is traceable freely, associated with veins of quartz and haematite, at Ballyjamesduff a little farther east. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 5 "Cat" to "Celt" Our knowledge of the Silurian fauna is at present derived entirely from rocks of marine origin, no fresh-water strata of such high antiquity having yet been met with. Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology In the Maecuru, another northern affluent, graptolites of Ordovician age have been discovered, and Silurian fossils are said to have been found in the Maraca. Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 4 "Bradford, William" to "Brequigny, Louis" In this formation alone about 450 species are known, and in the Silurian these increase to 1,200; and here the group culminates. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z On top of the Silurian begins the "Devonian" age, in which is found the old red sandstone, as well as limestone and slate; and here begin to be found the fossils of land-plants. Nature's Miracles, Volume 1 Familiar Talks on Science—World-Building and Life. Earth, Air and Water. They belong entirely to the Ordovician and Silurian periods; they have yielded few fossils, and much work remains to be done upon them before the stratigraphical subdivisions can be clearly defined. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 3 "Capefigue" to "Carneades" The remains of fish are as yet confined to the upper part of the Silurian series; but some of these belong to placoid fish, which occupy a high grade in the scale of organization. Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology The province of New Brunswick exhibits approximately parallel but subordinate ridges, with wide intervening areas of nearly flat Silurian and Carboniferous rocks. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 2 "Camorra" to "Cape Colony" We shall find, however, that in the Upper Silurian, fishes made their appearance, and in the Carboniferous amphibian reptiles, and that, before the close of the Palæozoic, vertebrate life in 85these forms had become predominant. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z The eyes of the trilobite of the old Silurian rocks are fitted for the same conditions with respect to light with those of existing animals of the same class. The Origin of the World According to Revelation and Science The mica-schists and Silurian slates of its eastern flank are seen in the diversified and hilly country on the pass over the shoulder of Mt. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 3 "Capefigue" to "Carneades" Thus, for example, on the borders of Wales and Shropshire we find the slaty beds of the ancient Silurian system curved and vertical, while the beds of the overlying carboniferous shale and sandstone are horizontal. Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology It must have grown in one of the ages that one always likes to hear of, but hates to study about, a paleozoic or Silurian or post-tertiary, or one of those times. Harper's Round Table, May 28, 1895 If we now turn to the Silurian, further evidence of land vegetation presents itself. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z On the Norwegian side the Cambrian is perhaps represented by the R�ros schists which lie at the base of a great series of crystalline schists, the probable equivalent of Ordovician and Silurian rocks. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 1 "Calhoun" to "Camoens" Wenlock Edge, running from south-west to north-east, is an escarpment of Silurian limestone, while the broad upland of Long Mynd, nearly parallel to it on the north, is a mass of Archaean rock. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 4 "England" to "English Finance" The fossils of the Devonian and Silurian strata in Europe and North America have led to the conclusion, that they were formed for the most part in deep seas, far from land. Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology Geology.—On the north a Silurian upland stretches, falling to the sea at Balbriggan, where fossiliferous strata contain contemporaneous volcanic rocks. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 7 "Drama" to "Dublin" The Devonian flora seems to have been introduced in the northern parts of the American continent at a time of warm and equable climate, and of elevation of new land out of the Silurian sea. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z Most of the Cambrian rocks were coloured as Silurian on the British official geological maps. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 1 "Calhoun" to "Camoens" Mid Wales is built up, for the most part, of Silurian or Ordovician rocks, practically free from igneous intrusions except in the south-west. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 4 "England" to "English Finance" A wide expanse of ocean, interspersed with islands, seems to have pervaded the northern hemisphere at the periods when the Silurian and carboniferous rocks were formed, and a warm and very uniform temperature then prevailed. Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology Geology.—The dominant feature in the geology of this county is the north-east and south-west strike forced upon the older rocks during earth-movements that set in at the close of Silurian times. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 6 "Dodwell" to "Drama" In the Lower Silurian such plants as existed must have experienced great restriction at the age of the Niagara or Wenlock limestone. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z The first animal with a backbone recorded its existence among the fossils found in rocks of the upper Silurian strata. Earth and Sky Every Child Should Know Easy studies of the earth and the stars for any time and place In the same two areas we find the Silurian rocks, shales and limestones with grits and flags. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 4 "England" to "English Finance" That part of the front which dates back to the Lower Silurian epoch ran south-southwest, but at some time during the Drift period it turned to the right about and drifted to the north-northeast. The Atlantic Monthly, Volume 16, No. 95, September 1865 Geology.—The foundation of this county is Silurian rock throughout, the slates and sandstones striking as a whole north-east, but giving rise to a country of abundant small hills. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 6 "Dodwell" to "Drama" The oldest air breathers at present known are Scorpions and insects allied to the modern May-flies, which have been found in the Silurian. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z The great inland sea that covered the middle portion of the continent during the Silurian and the Devonian periods, became shallow by the deposit of vast quantities of sediment. Earth and Sky Every Child Should Know Easy studies of the earth and the stars for any time and place O a' the airts the wind can blaw I dearly like the west, For there Silurian beds abound, The beds that I lo'e best; There's limestone blue, and sandstone too, Wi' slate and shale between. Punch - Volume 25 (Jul-Dec 1853) Boulder-beds also occur in the Silurian rocks of Scotland and North America, and according to Professor Dawson, even in the Huronian, older than our Cambrian. Island Life Or the Phenomena and Causes of Insular Faunas and Floras He was also the first to indicate the presence of Silurian rocks, and to determine the age of the coal-bearing rocks in New South Wales. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 4 "Cincinnatus" to "Cleruchy" This strikes us especially in the comparatively simple and homogeneous life-dynasties of the Palæozoic, when for example we find the same types of Silurian Graptolites, Trilobites and Brachiopods appearing simultaneously in Australia, America, and Europe. The Chain of Life in Geological Time A Sketch of the Origin and Succession of Animals and Plants 2011-06-01T02:00:24.880Z The ancient rocks, in which these lower forms of life have left their fossils, are known as the Silurian system. Earth and Sky Every Child Should Know Easy studies of the earth and the stars for any time and place The same series again appears amidst the Lower Silurian beds of Co. Volcanoes: Past and Present Lastly, the ancient Silurian limestones, which are widely spread in the high Arctic regions, contain abundance of corals and cephalopodous mollusca resembling those from the same deposits in more temperate lands. Island Life Or the Phenomena and Causes of Insular Faunas and Floras On the east, the folding has brought up two bold masses of Old Red Sandstone, with Silurian cores. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 4 "Cincinnatus" to "Cleruchy" It is only necessary, for this purpose, to inspect the imperfect maps that have been published of the Silurian and even tertiary periods. History of the Intellectual Development of Europe, Volume I (of 2) Revised Edition Silurian Molluscs Seaweeds I. Fire-formed No life No life It is by dying that the creatures of the sea write their epitaphs. Earth and Sky Every Child Should Know Easy studies of the earth and the stars for any time and place Upper Silurian Period.—Volcanic rocks of this stage are only known in Ireland, on the borders of Cos. Volcanoes: Past and Present Geology.—The rocks entering into the geological structure of the Cheviots belong to the Silurian, Old Red Sandstone and Carboniferous systems. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 1 "Châtelet" to "Chicago" Silurian Bond is made by a fellowship of geologists, and for Chelsea Bank they have a factory on the bank of the Thames at Cheyne Walk. Punch, or the London Charivari, Volume 158, June 2, 1920 Snakes developed in the Silurian Era, some twenty million years ago. Carmen Ariza The rocks that bear the record of these living things in their fossils, form strata of great thickness that overlie the Silurian deposits. Earth and Sky Every Child Should Know Easy studies of the earth and the stars for any time and place Changes were taking place from the beginning of the period in the relative importance of genera; several Silurian forms dropped out, and new types were coming in. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 3 "Destructors" to "Diameter" The oldest strata, which are of Upper Silurian age, form inliers that have been exposed by the denudation of the younger palaeozoic rocks. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 1 "Châtelet" to "Chicago" Until some twelve years ago, Goniatites had not been found lower than the Devonian rocks; but now, in Bohemia, they have been found in rocks classed as Silurian. Essays: Scientific, Political, & Speculative, Vol. I There are remains in the Silurian which show that there must have been a few fishes at that time. The Meaning of Evolution The Devonian sea was smaller than the Silurian. Earth and Sky Every Child Should Know Easy studies of the earth and the stars for any time and place The corals were abundant individually and varied in form; and they are so distinctive of the period that no Devonian species has yet been found either in the Silurian or in the Carboniferous. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 3 "Destructors" to "Diameter" Were the trilobites of the Silurian system,—at one period, as their remains testify, more than equally abundant,—creatures of similar habits? The Cruise of the Betsey or, A Summer Ramble Among the Fossiliferous Deposits of the Hebrides. With Rambles of a Geologist or, Ten Thousand Miles Over the Fossiliferous Deposits of Scotland They might be expected to make their appearance along with the predaceous crustaceans; as they do in the uppermost Silurian rocks. Essays: Scientific, Political, & Speculative, Vol. I In this Silurian time certain of these lungfish were perhaps trapped in the basin in the marsh by the uplifting of the border. The Meaning of Evolution In the upper beds of the Upper Silurian, as has been already remarked, Lycopodites are the only terrestrial plants yet found. The Testimony of the Rocks or, Geology in Its Bearings on the Two Theologies, Natural and Revealed Like the Silurian formations described elsewhere, they remain to this day nearly as flat and unaltered as they were originally laid down. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 3 "Destructors" to "Diameter" Geology.—The greater portion of the hilly region in the south of the county forms part of the Silurian tableland of the south of Scotland. Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 1 "Austria, Lower" to "Bacon" "The mere presence of a graptolite," he says, "will at once decide that the enclosing rock is Silurian;" and he says this, notwithstanding repeated warnings against such generalizations. Essays: Scientific, Political, & Speculative, Vol. I After these forms the most abundant fossils we find in Silurian times were creatures that at first sight looked as if they might be related to the clams. The Meaning of Evolution The fauna of the Silurian System bears in all its three great types the stamp of a fashion peculiarly antique, and which, save in a few of the mollusca, has long since become obsolete. The Testimony of the Rocks or, Geology in Its Bearings on the Two Theologies, Natural and Revealed The upper part of the Lower Devonian, the sandy shale of Steinach, rests unconformably upon Silurian rocks. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 3 "Destructors" to "Diameter" Some of the Silurian sediments of the Girvan province are highly fossiliferous, but the order of succession is determined by the graptolites. Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 1 "Austria, Lower" to "Bacon" Once more, certain red conglomerates and grits on the north-west coast of Scotland, long supposed from their lithological aspect to belong to the Old Red Sandstone, are now identified with the Lower Silurians. Essays: Scientific, Political, & Speculative, Vol. I The third group of the mollusks to which the nautilus and squid of to-day belong is very abundantly represented in the Silurian by fossils with coiled-up shells. The Meaning of Evolution The Silurian System has not yet afforded trace of any other vertebral animal. The Testimony of the Rocks or, Geology in Its Bearings on the Two Theologies, Natural and Revealed They had come into existence late in Silurian times; but it is in the Old Red strata that their remains are most fully preserved. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 3 "Destructors" to "Diameter" Old Red Sandstone and his wife over there are well enough at a lion soirée, but how would their Silurian manners shine at the Patriarchs' ball? The Faith Doctor A Story of New York Yes; the genus lingula, the species appearing in all the ages, was "connected by an unbroken series of generations from the lowest Silurian stratum to the present day."—Origin of Species, pp. The Christian Foundation, Or, Scientific and Religious Journal, Volume 1, January, 1880 The first of the three sections into which this period of life is divided is known as the Silurian age, the age of invertebrates. The Meaning of Evolution The oldest known reptiles appear just a little before the close of the Old Red Sandstone, just as the oldest known fishes appeared just a little before the close of the Silurian System. The Testimony of the Rocks or, Geology in Its Bearings on the Two Theologies, Natural and Revealed In the north of England this series rests unconformably upon the Lower Old Red and the Silurian. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 3 "Destructors" to "Diameter" Certain Foraminifera have not varied since the Silurian epoch. Creative Evolution In the period of the Upper Silurian fish, properly so called, and of a very perfect organisation, had taken precedence of the crustacean. The World's Greatest Books — Volume 15 — Science This period is called the age of invertebrates because, although there is an enormous wealth of animal and plant life in the Silurian, there are no backboned animals except the lowest kinds of fishes. The Meaning of Evolution There appear no traces of a terrestrial vegetation until we reach the uppermost beds of the Upper Silurian System. The Testimony of the Rocks or, Geology in Its Bearings on the Two Theologies, Natural and Revealed Over this system lie beds which have yielded in succession Ordovician and Silurian fossils, forming altogether a compact division which has been distinguished locally as the Muth system. The Panjab, North-West Frontier Province, and Kashmir Hence their somewhat impulsive temperament, and the occurrence of Celtic or Silurian names, such as the following, indicative of the character of the places they designate:— p. 144Dean i.e. The Forest of Dean An Historical and Descriptive Account We have seen that fishes, which are the oldest vertebrates, first appear in the Silurian strata, and are found in all the succeeding formations up to the birds of the Tertiary Period. The World's Greatest Books — Volume 15 — Science He considers the first insect to have appeared after the Silurian period, viz., in the Devonian. Our Common Insects A Popular Account of the Insects of Our Fields, Forests, Gardens and Houses No insects have yet been detected in the Silurian or Old Red Sandstone Systems. The Testimony of the Rocks or, Geology in Its Bearings on the Two Theologies, Natural and Revealed Of fossiliferous systems there is a fine display of material ranging in age from Silurian to Upper Trias, and additional interest is added by the long-continued volcanic eruptions of the "Panjál trap." The Panjab, North-West Frontier Province, and Kashmir The country consisted of upright strata of Silurian limestone running from east to west, and at certain places containing fossils resembling those of Gotland. The Voyage of the Vega round Asia and Europe, Volume I and Volume II The rocks of these two earlier periods are those of the Cambrian and Silurian groups. The World's Greatest Books — Volume 15 — Science Thus the views previously entertained regarding the invertebrate character of the fauna of the Silurian epoch, have ultimately remained unaffected, so far as these Potsdam slabs are concerned. Chambers's Edinburgh Journal, No. 459 Volume 18, New Series, October 16, 1852 The articulata of the Silurian period bore a still more peculiar character. The Testimony of the Rocks or, Geology in Its Bearings on the Two Theologies, Natural and Revealed I have shown you—corroborating Scripture—the earth, without form and void, the awful monsters of the Silurian age, and Man in the Garden of Eden. Five Hundred Dollars First published in the "Century Magazine" Several of the most eminent geologists, with Sir E. Murchison at their head, are convinced that we see in the organic remains of the lowest Silurian stratum the dawn of life on this planet. On the Origin of Species by Means of Natural Selection or the Preservation of Favoured Races in the Struggle for Life. (2nd edition) There is less doubt respecting the existences of the Silurian rocks. The World's Greatest Books — Volume 15 — Science Since the immeasurably remote Silurian period, sharks and dog-fish have probably remained without any essential changes of condition, and consequently without any essential changes of structure, down to the present day. Text Book of Biology, Part 1: Vertebrata The Silurian deposits of our country have not yet furnished us with any unequivocal traces of a terrestrial vegetation. The Testimony of the Rocks or, Geology in Its Bearings on the Two Theologies, Natural and Revealed Now it will be a moderate computation to allow 25,000,000 years for the deposition of the strata down to and including the Upper Silurian. On the Genesis of Species Perhaps we are the trilobites of a new Silurian period; well, trilobites were painfully common, but we need not be. The Master-Knot of Human Fate In the very earliest fossiliferous rocks of all, the Precambrian formation, there are remains of Molluscs, Trilobites and Gigantostraca, similar to those which flourished in Cambrian and Silurian times. Form and Function A Contribution to the History of Animal Morphology In the Silurian period in which the peopling of the seas went on apace, there was the first known attempt at colonising the dry land. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told It was held only a few years ago, that the Silurians of the United States had their plants allied to the Lepidodendron. The Testimony of the Rocks or, Geology in Its Bearings on the Two Theologies, Natural and Revealed For when those Upper Silurian strata were formed, organic evolution had already run a great part of its course, perhaps the longest, slowest, and most difficult part of that course. On the Genesis of Species But instead of that we discover, away down in the Silurian strata, at the very beginning of life, all the four kingdoms—the radiates, the mollusks, the articulates, and the fish! Fables of Infidelity and Facts of Faith Being an Examination of the Evidences of Infidelity The break in the supposed chain of evolution between the invertebrates and the highly organized vertebrates of the Lower Silurian is one of the greatest in the whole geological record. Evolution An Investigation and a Critique For in Silurian rocks there are fossil scorpions, and that implies ability to breathe dry air—by means of internal surfaces, in this case known as lungbooks. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told It has been shown, too, by Sir Roderick Murchison, that the supposed Silurian plants of Oporto are in reality Carboniferous, and owe their apparent position to a reverse folding of the strata. The Testimony of the Rocks or, Geology in Its Bearings on the Two Theologies, Natural and Revealed Principal Dawson calls the oldest the Laurentian, and places the first vertebrates in the Silurian. What is Darwinism? When asked for the missing links between existing species, he refers us to the undiscovered fossiliferous strata below the Silurian. Fables of Infidelity and Facts of Faith Being an Examination of the Evidences of Infidelity As it wound down the face of the hill, it suggested a vast Silurian monster, each wagon top a vertebra, crawling forward with definite purpose. The Emigrant Trail The Nautiloids began in the Cambrian, reached their golden age in the Silurian, and began to decline markedly in the Carboniferous. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told The slab belongs to the lower Silurian formation, the first in which organic remains are found. Scientific American, Volume 40, No. 13, March 29, 1879 A Weekly Journal of Practical Information, Art, Science, Mechanics, Chemistry, and Manufactures I did not trouble my head much about the matter; whether we were among the combustible carbon, Silurians, or primitive soil, I neither knew nor cared to know. A Journey to the Centre of the Earth The Roman enslaved it, but left Caledonia and Hibernia free, the Cambrian, the Silurian, the Cornishman half-subjugated. Post-Prandial Philosophy They occur in rocks of the Cambrian or Silurian age in eastern Tennessee and western North Carolina; they are also found in India beyond the limits to which glaciers have attained in modern times. Outlines of the Earth's History A Popular Study in Physiography By some geologists it is called the Silurian System, it being largely developed at the surface of a district of western England formerly occupied by the Silures. An Expository Outline of the "Vestiges of the Natural History of Creation" With a Notice of the Author's "Explanations:" A Sequel to the Vestiges The formation is upper Silurian or lower Devonian, a transition to gneiss, but not highly metamorphic. To The Gold Coast for Gold, Vol. II A Personal Narrative It was quite natural that I should expect to find these signs, for during the Silurian period the seas contained no fewer than fifteen hundred different animal and vegetable species. A Journey to the Centre of the Earth Only after a certain housecleaning and purification of the elements do higher forms appear; the vast accumulation of Silurian limestone must have hastened the age of fishes. The Breath of Life Opposite Fishkill is Newburgh, which is in the great valley of Lower Silurian or Cambrian limestone and slate. The Hudson Three Centuries of History, Romance and Invention It is found also in North Wales and in the north of England, in beds of great thickness, and in Scotland, but there the Silurian rocks are more feebly represented. An Expository Outline of the "Vestiges of the Natural History of Creation" With a Notice of the Author's "Explanations:" A Sequel to the Vestiges "A world without us!" it says, as a heady young Cephalaspis might have said it in the old Silurian sea. Certain Personal Matters The vertebrates first make their appearance, in the shape of fishes, towards the close of the Silurian period, the second of the great geological epochs. Falling in Love With Other Essays on More Exact Branches of Science In what sense can Loligo or Spirula be said to be more specialized, or less embryonic, than Belemnites; or the modern species of Lamellibranch and Gasteropod genera, than the Silurian species of the same genera? Lay Sermons, Addresses and Reviews The central sea of Asia, the Tethys, extended westwards and now joined with the European Paleozoic sea; and deposits of Ordovician and Silurian age were laid down:—the Muth deposits. The Birth-Time of the World and Other Scientific Essays In the Silurian deposit the vestiges of life become more abundant, the number of species extended, and important additions made in the traces of sea plants and fishes. An Expository Outline of the "Vestiges of the Natural History of Creation" With a Notice of the Author's "Explanations:" A Sequel to the Vestiges Epoch, Glacial, 86; Silurian and Devonian, rich array of types, 93; Cenozoic, 96. The Doctrine of Evolution Its Basis and Its Scope They follow each other from east to west in a narrower area, just as the Azoic, Silurian, and Devonian deposits follow each other from north to south in the northern part of the United States. The Atlantic Monthly, Volume 12, No. 70, August, 1863 On what amount of similarity of their faunæ is the doctrine of the contemporaneity of the European and of the North American Silurians based? Lay Sermons, Addresses and Reviews This mica was probably formed in the granite of Leinster in late Silurian or in Devonian times. The Birth-Time of the World and Other Scientific Essays Perhaps, in strict fact, the cephalopoda do not appear till a later time, that of the Silurian rocks. An Expository Outline of the "Vestiges of the Natural History of Creation" With a Notice of the Author's "Explanations:" A Sequel to the Vestiges Except for the fishes, there were no very great changes in the character of the life from that which existed in the earlier time of the Cambrian and Silurian. Young Folks' Library, Volume XI (of 20) Wonders of Earth, Sea and Sky Caradoc calls his warriors, And loud the bugles blow; On rushed the brave Silurians, And fell beneath the foe. Welsh Lyrics of the Nineteenth Century Within was a large room with fairly smooth walls and ceiling of Silurian rock and sandstone. Campfire Girls in the Allegheny Mountains or, A Christmas Success against Odds Silurian It will be noticed by those who have any knowledge of geological divisions, that in this diagram I consider the Carboniferous epoch as forming a part of the Secondary age. The Atlantic Monthly, Volume 12, No. 69, July, 1863 In peace it is always best to prepare for war, and I trust you will lend your countenance to the able men who are investigating the Lower Silurian age. Peck's Compendium of Fun We first find many certain evidences of life in the rocks which lie on top of the arch�an rock, and are known as the Cambriani and Silurian periods. Young Folks' Library, Volume XI (of 20) Wonders of Earth, Sea and Sky A fossil spider has been found in the Carboniferous, and scorpions in the Upper Silurian rocks of Scotland, Sweden, and the United States. Darwinism (1889) His ponderous scientific brain told him one thing in plain terms, and yet he was leaning on the words of a chit that wouldn't know a carboniferous vertebra from an Upper Silurian gerumpsus. Ma Pettengill If the reader will take the trouble to look on any geological map of Europe, he will see an extensive patch of Silurian rock in the centre of Sweden and Norway. The Atlantic Monthly, Volume 12, No. 69, July, 1863 Day after day, night after night, Queed sat at his tiny table poring over back files of the Post, examining Colonel Cowles's editorials as a geologist examines a Silurian deposit. Queed Still, at the end of the Silurian, the life of the world had climbed some steps higher in structure and in intelligence. Young Folks' Library, Volume XI (of 20) Wonders of Earth, Sea and Sky The lowest forms of vertebrates are the fishes, and these appear first in the geological record in the Upper Silurian formation. Darwinism (1889) Whereupon the lady drew herself up and remarked in the clipped accent of a parrot: "No, sir; it's a carboniferous trilobite of the Upper Silurian." Ma Pettengill But in their geological significance they indicate all the oscillations and disturbances of the soil throughout the region over which the Silurian deposits have been traced in Europe. The Atlantic Monthly, Volume 12, No. 69, July, 1863 Generalised section of the Lower Silurian rocks of Wales. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science It is marked by the rapid extension of the fishes; for, although the fishes began in the uppermost Silurian, they first became abundant in this time. Young Folks' Library, Volume XI (of 20) Wonders of Earth, Sea and Sky The limestones of the Silurian series are the principal sources of supply, the quarries about Joliet being among the largest in the United States. Final Report of the Louisiana Purchase Exposition Commission That there," she glibly rattled off, "is the organic remains of a three-toed woolly bronsolumphicus of the carboniferous limestone, or Upper Silurian trilobite period. Ma Pettengill This represents that sheet of water gradually to be filled by the accumulation of Silurian deposits and afterwards raised by a later disturbance. The Atlantic Monthly, Volume 12, No. 69, July, 1863 Generalised section of the Lower Silurian rocks of North America. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science The higher country there is granitic although, on both rivers, limestone also abounds in which the corals seem to belong to Mr. Murchison's Silurian system. Three Expeditions into the Interior of Eastern Australia, Volume 2 This accounts for the great profusion of Silurian organic remains in that neighborhood. The Atlantic Monthly, Volume 11, No. 67, May, 1863 D. 13.—The unremitting pressure of these two garrisons crushed out at last the Silurian resistance. Early Britain—Roman Britain Crustaceans and insects appeared as early as Silurian times. Creation and Its Records If the Graptolites belong to certain genera, we may be quite certain that we are dealing with Lower Silurian rocks. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Again, older than the true carboniferous age, are the Silurian anthracites of Co. The Story of a Piece of Coal What It Is, Whence It Comes, and Whither It Goes "It isn't a rock of the Old Silurian." We Girls: a Home Story The Silurians, of Glamorgan, are specially noted as examples of this "black" physique, and a connection has been imagined between them and the Basques of Iberia, an idea originating with Strabo. Early Britain—Roman Britain Land insects, as might naturally be expected, go back to the times when land vegetation was sufficiently established, and appear gradually all along the line from the Silurian onwards. Creation and Its Records Furthermore, if certain special forms are present, we may be even able to say to what exact subdivision of the Lower Silurian series they belong. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science The fishing-ground of the geologist in the Silurian and Devonian periods is even more circumscribed than his, and belongs, besides, not to a living, but to a dead world, far more difficult to decipher. The Atlantic Monthly, Volume 11, No. 66, April, 1863 This is the beach of the Lower Silurian sea when it washed the shores of an Archæan island, now the Black Hills. Scientific American Supplement, No. 446, July 19, 1884 But it isn't her name, exactly, only Saxon for Craydocke; suggestive of obstinacy and the Old Silurian,—an ancient maiden who infests our half the wing. A Summer in Leslie Goldthwaite's Life. The lower country consists of clay-slate and sandstone, containing fossils, very closely related to, but not identical with, those found in the Silurian formations of Europe; the hills are formed of white granular quartz rock. The Voyage of the Beagle Similarly, the species and genera which we now regard as characteristic of the Lower Silurian, may at some future time be found to have survived into the Upper Silurian period. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Even in the Carboniferous period but few are to be found: they had their day in the Silurian and Devonian ages. The Atlantic Monthly, Volume 11, No. 66, April, 1863 It was very fierce, and the Old Silurians were afraid of it, but this is a tame one. What Is Man? and Other Essays Trilobites were very common in the Silurian and Devonian periods, but became extinct at the close of the Paleozoic. The Gutenberg Webster's Unabridged Dictionary Section T, U, V, and W The saliferous beds of New York State belong largely to the Salina period of the Upper Silurian. The Gutenberg Webster's Unabridged Dictionary Section S There are many places—to take a single example—where one may see the the Silurian rocks, the Devonian, and the Carboniferous rocks succeeding one another regularly, and in their proper order. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Now, though we have not found as yet any complete specimens of Silurian fishes, their disconnected remains are scattered profusely in the early deposits. The Atlantic Monthly, Volume 11, No. 66, April, 1863 Geologically the Andes are yet in a chaotic and formative condition; huge slides of Silurian slates and diorite are of frequent occurrence. Under the Andes They are unfossiliferous, and in the absence of undoubted Cambrian, Ordovician and Silurian strata in Africa they may be regarded as of older date than any of these formations. The Project Gutenberg Encyclopedia Volume 1 of 28 The Graptolites, occurring in the bituminous shales of the Silurian sandstone period, afford only another instance of the same law to which we have called the attention of our readers. Life: Its True Genesis There are, however, many more localities in which one would find the Carboniferous rocks resting unconformably upon the Silurians without the intervention of any strata which could be referred to the Devonian period. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Such marks are as distinct on the oldest Silurian rocks as if they had been made yesterday. The Atlantic Monthly, Volume 11, No. 66, April, 1863 That many limestones are more or less charged with petroleum is well known; and in addition to those mentioned above, the Silurian limestone at Collingwood, Canada, may be cited as an example. Scientific American Supplement, No. 362, December 9, 1882 Some unfossiliferous conglomerates, sandstones and dolomites in South Africa and on the west coast are considered to belong to the Cambrian, Ordovician and Silurian formations, but merely from their occurrence beneath strata yielding Devonian fossils. The Project Gutenberg Encyclopedia Volume 1 of 28 Mr. Goss in his preface to the second edition of his book notes that what is probably a still older insect has been found in the lower Silurian in Sweden. The Naturalist on the Thames The Devonian might have been deposited upon the Silurian, and then the whole might have been elevated above the sea, and subjected to an amount of denudation sufficient to remove the Devonian strata entirely. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science I subjoin a woodcut of a Silurian Coral, which does not, however, show the peculiar internal structure, but gives some idea of the general appearance of the old Hydroid Corals. The Atlantic Monthly, Volume 11, No. 66, April, 1863 Of these we have examples in the beds of graphite in the Laurentian rocks of Canada, and of anthracite of the lower Silurian strata of Upper Church and Kilnaleck, Ireland. Scientific American Supplement, No. 362, December 9, 1882 In Cape Colony the Silurian age of the Table Mountain Sandstone is based on such evidence. The Project Gutenberg Encyclopedia Volume 1 of 28 Remains of such plants were discovered in the Silurian rocks. The Naturalist on the Thames In this case, when the land was again submerged, the Carboniferous rocks, or any younger formation, might be deposited directly upon Silurian strata. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science The annexed wood-cut represents one of these Brachiopods, which form a very characteristic type of the Silurian deposits. The Atlantic Monthly, Volume 11, No. 66, April, 1863 Such an aggregation of actual, living Silurian monsters, any one of which would make a man a fortune to-day, if it could be kept on ice and exhibited for one season only. Remarks And it is remarkable that the Silurian fishes are here only represented in genera; the whole of the species of that era had already passed away. Vestiges of the Natural History of Creation The gravel outside, at least, is an old friend; it consists of broken bits of gray Silurian rock, and white quartz among it; and one touch of Siluria makes the whole world kin. At Last In no case, however, do we ever find the Devonian resting upon the Carboniferous, or the Silurian rocks reposing on the Devonian. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Some of the shells of this kind belonging to the Silurian deposits are enormous: giants of the sea they must have been in those days. The Atlantic Monthly, Volume 11, No. 66, April, 1863 It stands true, certainly, of the ancient Silurian rocks of Wales, Cumberland, Ireland, and Scotland. Town Geology In the old red sandstone, the marine plants, of which faint traces are observable in the Silurians, continue to appear. Vestiges of the Natural History of Creation The rocks are probably Silurian; and if so, of quite immeasurable antiquity. At Last Whenever muddy sediments are found in the Cambrian and Silurian formations, there we are tolerably sure to find Trilobites, though they are by no means absolutely wanting in limestones. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science In what sense can Loligo or Spirula be said to be more specialised, or less embryonic, than Belemnites; or the modern species of Lamellibranch and Gasteropod genera, than the Silurian species of the same genera? Discourses Biological and Geological Essays For, throughout great tracts of Russia, and in parts of Norway and Sweden, Sir Roderick Murchison discovered our own Silurian beds, recognisable from their peculiar fossils. Town Geology And, in view of the facts of geology, it follows that all living animals and plants "are the lineal descendants of those which lived long before the Silurian epoch." Darwiniana : Essays — Volume 02 It is divided into four long periods, the Silurian, Devonian, Carboniferous, and Permian. The Evolution of Man — Volume 2 Orthoceras, with its straight, partitioned shell, which we shall find in an immense variety of forms in the Silurian rocks. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science "It is plain," he said, "that the basalt monadnock on which we stand is a carboniferous upthrust of metamorphosed schists, shales and conglomerate, probably Mesozoic or at least early Silurian." The Cruise of the Kawa They consist of fragments of granite, syenite and greenstone, as well as of Devonian and Silurian rocks, some of them of large size. The Antiquity of Man Even Pictet, in the second edition of his Paleontology, still considers Pleurotomaria as extinct, and as belonging to the fossiliferous formations which extend from the Silurian period to the Tertiary. Louis Agassiz: His Life and Correspondence On the other hand, we have a great variety of specimens of this group in the fossil state, from the Upper Silurian onward. The Evolution of Man — Volume 2 In consequence of the above, Silurian districts usually present the bold, rugged, and picturesque outlines which are characteristic of the older "Primitive" rocks of the earth's crust in general. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science I understand," he said, fixing Tom Phipps with a stern glance of inquiry, as they started for the mine, "that Silurian species have been found in the limestones hereabouts. The Pony Rider Boys in the Ozarks Or, the Secret of Ruby Mountain As to the Mollusca, which afford the most unbroken series of geological medals, the highest of that class, the Cephalopoda, abounded in older Silurian times, comprising several hundred species of chambered univalves. The Antiquity of Man So the ossification of the vertebral column takes place progressively, from the Silurian to the middle Jurassic. Time and Change On the other hand, the more ancient or Silurian group suffered only a local derangement, and neither in Wales nor elsewhere are all the rocks of that age found to be curved or vertical. The Harvard Classics Volume 38 Scientific Papers (Physiology, Medicine, Surgery, Geology) All, therefore, that can be attempted here, is to select two typical areas—such as Wales and North America and to briefly consider the grouping and divisions of the Lower Silurian in each. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science The Silurian rocks are succeeded by rocks which present two distinct characters, but are probably contemporaneous, the Devonian and the old Red Sandstone. Story of Creation as Told By Theology and By Science The Stromatopora are among the chief limestone builders of the Silurian and Devonian periods. The Elements of Geology The Silurian was the great age of trilobites; the Devonian, the age of fishes; Mesozoic times swarm with the gigantic reptiles; and in Tertiary times the mammals are dominant. Time and Change Thus, for example, on the borders of Wales and Shropshire, we find the slaty beds of the ancient Silurian system inclined and vertical, while the beds of the overlying carboniferous shale and sandstone are horizontal. The Harvard Classics Volume 38 Scientific Papers (Physiology, Medicine, Surgery, Geology) The Protozoans appear to have flourished extensively in the Lower Silurian seas, though to a large extent under forms which are still little understood. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Thin layers of trap, only a few inches thick, alternate in some parts of Shropshire and Montgomeryshire with sedimentary strata of the Lower Silurian system. The Student's Elements of Geology The description of other types of corals will be given under the Silurian, where they first became abundant. The Elements of Geology He is a debtor to Cambrian and Silurian times, to the dragons and saurians and mastodons that have roamed over the earth. Time and Change It could not be otherwise, for in the Silurian age the seas contained at least fifteen hundred vegetable and animal species. A Journey to the Interior of the Earth The most abundant, and at the same time the least understood, of Lower Silurian Protozoans belong, however, to the genera Stromatopora and Receptaculites, the structure of which can merely be alluded to here. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Nevertheless, these greenstones appear to belong, like the lavas, to the Lower Silurian period. The Student's Elements of Geology They became extinct at the end of the Silurian. The Elements of Geology These caverns are carved from the Silurian limestone, although they are considered to date from the Tertiary period. See America First Species of these genera occur in the Silurian, Devonian, and Carboniferous strata of Europe. Volcanic Islands Lastly, in the fossils known as Receptaculites and Ischadites we are also presented with certain singular Lower Silurian Protozoans, which may with great probability be regarded as gigantic Foraminifera. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science These hills are 1900 feet high above the sea, and consist of conglomerates and sandstones of Upper Devonian age, resting on the inclined edges of grits and slates of Lower Devonian and Upper Silurian date. The Student's Elements of Geology In America the Silurian is not separated from the Devonian by any mountain-making deformation or continental uplift. The Elements of Geology You must have worked hard, and got your Silurian subject well in your head, to have profited by so short an excursion. More Letters of Charles Darwin — Volume 2 Mr. Lonsdale remarks, that all these fossils have undoubtedly a Palaeozoic character, and that probably they correspond in age to a division of the system above the Silurian formations. Volcanic Islands They constitute one of the most important groups of Silurian fossils, and are of the greatest value in determining the precise stratigraphical position of the beds in which they occur. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science In Radnorshire there is an example of twelve bands of stratified trap, alternating with Silurian schists and flagstones, in a thickness of 350 feet. The Student's Elements of Geology Ever since the middle of the Silurian, the Sierra trough had been sinking, though no doubt with halts and interruptions, until it contained nearly twenty-five thousand feet of sediment. The Elements of Geology And this is a comfort to me when mentally comparing the Silurian and Recent organisms. More Letters of Charles Darwin — Volume 1 Oh, come, and—in technical speech— We'll walk this Devonian shore, Or on some Silurian beach We'll wander, my love, evermore. Complete Poetical Works For this reason, the common Lower Silurian Corals are separated to form a distinct group under the name of Rugose Corals or Rugosa. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science The gold found in the United States, in the mountainous parts of Virginia, North and South Carolina, and Georgia, occurs in metamorphic Silurian strata, as well as in auriferous gravel derived from the same. The Student's Elements of Geology The Silurian and Devonian strata thin out as they approach this area and seem never to have deposited upon it. The Elements of Geology Again, the recent discovery of plants rather low down in our Silurian beds is very important. Life and Letters of Charles Darwin — Volume 2 And oh, if Earth's strata contains In its lowest Silurian drift, Or palaeozoic remains The same, 'tis your lover's free gift! Complete Poetical Works The Cystideans are principally, and indeed nearly exclusively, Silurian fossils; and though occurring in the Upper Silurian in no small numbers, they are pre-eminently characteristic of the Llandeilo-Caradoc period of Lower Silurian time. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science In Australia it has been worked successfully not only in alluvium, but in vein-stones in the native rock, generally consisting of Silurian shales and slates. The Student's Elements of Geology During the Silurian period the Mississippi valley region was covered with a quiet, shallow, limestone-making sea, which received little waste from the low lands which bordered it. The Elements of Geology The summing up of the Niagara chapter appeared to me the grandest part; I was also deeply interested by your discussion on the origin of the Silurian formations. Life and Letters of Charles Darwin — Volume 1 He was already old in society, and belonged to the Silurian horizon. The Education of Henry Adams The remaining Lower Silurian groups of Mollusca can be but briefly glanced at here. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Christiania, Euritic porphyry at. —, granite veins in Silurian strata of. —, quartz vein in gneiss at. The Student's Elements of Geology At the same time the western land was perhaps connected with the eastern land of Appalachia across Arkansas and Mississippi; for toward the south the Silurian sediments indicate an approach to shore. The Elements of Geology She would have expected him to have made that one of his first purchases—the more so that paper is so very cheap, especially that rather dirty-looking grey Silurian paper. The Lodger Adams found him most useful; perhaps quite the most useful of all these great authorities who were the stock-in-trade of the newspaper business; the accumulated capital of a Silurian age. The Education of Henry Adams Opinions differ as to whether this sandstone is to be regarded as the highest bed of the Upper Silurian or the base of the Devonian. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Several of the species are believed by Mr. Salter to be identical with Lower Silurian fossils of Canada and the United States. The Student's Elements of Geology In this brief sketch it is quite impossible to relate the many changes of species and genera during the Silurian. The Elements of Geology Several eminent geologists, with Sir R. Murchison at their head, were until recently convinced that we beheld in the organic remains of the lowest Silurian stratum the first dawn of life. The Origin of Species by means of Natural Selection, 6th Edition The sea of the Lower Silurian era was capable of supporting fish, but no fish existed. A History of Science — Volume 4 We thus see that in America, as in Britain, no other line than an artificial one can be drawn between the Upper Silurian and the overlying Devonian. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Metamorphic Strata of older date than the Silurian and Cambrian Rocks. The Student's Elements of Geology The lands were probably clad with verdure during Silurian times, if not still earlier; for some rare remains of ferns and other lowly types of vegetation have been found in the strata of that system. The Elements of Geology There are three great series of strata beneath the Silurian system in Canada, in the lowest of which the Eozoon is found. The Origin of Species by means of Natural Selection, 6th Edition For example, in some regions Silurian rocks are directly overlaid by the coal measures; but elsewhere this sudden break is filled in with the Devonian rocks that tell of a great "age of fishes." A History of Science — Volume 3 As regards the life of the Upper Silurian period, we have, as before, a number of so-called "Fucoids," the true vegetable nature of which is in many instances beyond doubt. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Although the precise age of such copper lodes can not be defined, we may safely affirm that they were either filled at the close of the Silurian or commencement of the Devonian period. The Student's Elements of Geology The Cambrian carries the Roman name of Wales, and the Ordovician and Silurian the names of tribes of ancient Britons which inhabited the same country. The Elements of Geology In the genus Lingula, for instance, the species which have successively appeared at all ages must have been connected by an unbroken series of generations, from the lowest Silurian stratum to the present day. The Origin of Species by means of Natural Selection, 6th Edition In the Silurian ages, invertebrates—brachiopods and crinoids and cephalopods—were the dominant types. A History of Science — Volume 3 The marine life of the Upper Silurian is in the main constituted by types of animals similar to those characterising the Lower Silurian, though for the most part belonging to different species. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Granite sending veins into Silurian strata and gneiss. The Student's Elements of Geology The limestone-making seas of the Silurian swarmed with corals, crinoids, and brachiopods. The Elements of Geology We will suppose the letters A to L to represent allied genera existing during the Silurian epoch, and descended from some still earlier form. The Origin of Species by means of Natural Selection, 6th Edition Several of the most eminent geologists, with Sir R. Murchison at their head, are convinced that we see in the organic remains of the lowest Silurian stratum the dawn of life on this planet. On the Origin of Species By Means of Natural Selection, or, the Preservation of Favoured Races in the Struggle for Life Coming to the Mollusca, we note the occurrence of the same great groups as in the Lower Silurian. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Sweden, Cambrian of. —, slow rise of land in. —, small thickness of Silurian strata in. The Student's Elements of Geology During the later Silurian and the Devonian the area was land and suffered vast denudation. The Elements of Geology Their remains are found only in the Palaeozoic rocks, and most abundantly in those of Silurian age. The Origin of Species by means of Natural Selection, 6th Edition The shore-tracts and the shallow water are narrowed, the struggle is intensified in them, and we pass into the Silurian age with a greatly reduced number but more advanced variety of animals. The Story of Evolution The higher groups of the Mollusca are also largely represented in the Upper Silurian. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science The "alum-schists," as they are called in Sweden, are horizontal argillaceous rocks which underlie conformably certain Lower Silurian strata in the mountain called Kinnekulle, south of the great Wener Lake in Sweden. The Student's Elements of Geology From this section infer that during early Silurian times the area was sea, and thick sea muds were laid upon it. The Elements of Geology The whole of this difficult question has thus been reopened, and we may yet have to record the first advent of Vertebrate animals in the Lower Silurian. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science In the Silurian age the sea advances once more, and the shore-waters expand. The Story of Evolution No one, however, can doubt the importance and reality of the Devonian series as an independent system of rocks to be intercalated in point of time between the Silurian and the Carboniferous. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Of Cystideans there are a few very remarkable forms, most of them peculiar to the Upper Silurian formation, as, for example, the Pseudocrinites, which was furnished with pinnated fixed arms, as represented in Figure 539. The Student's Elements of Geology Chain corals became extinct at the close of the Silurian, but other corals were extremely common in the Devonian seas. The Elements of Geology In considering the general succession of the Upper Silurian beds, we shall, as before, select Wales and America as being two regions where these deposits are typically developed. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Small forests of these sea-lilies adorn the floor of the Silurian ocean, and their broken and dead frames form whole beds of limestone. The Story of Evolution In no country in the world, probably, is there a finer or more complete exposition of the strata intervening between the Silurian and Carboniferous deposits than in the United States. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science The Brachiopods, of which there are 66 species, are almost all Upper Silurian. The Student's Elements of Geology The sharks of the Silurian and Devonian are known to us chiefly by their teeth and fin spines, for they were unprotected by scales or plates, and were devoid of a bony skeleton. The Elements of Geology These beds are probably to be regarded as the highest member of the Upper Silurian; but they are sometimes looked upon as passage-beds into the Old Red Sandstone, or as the base of this formation. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Of 250 species only a dozen linger in the Silurian strata, though a new and more advanced type—the Blastoid—holds the field for a time. The Story of Evolution No completely natural line can thus be indicated, dividing the Devonian in this region from the Silurian on the one hand, and the Carboniferous on the other hand. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Notwithstanding the antiquity of this Russian formation, it should be stated that both of these genera of brachiopods have been also found in the Upper Silurian of England, i.e. The Student's Elements of Geology In the Cambrian, Ordovician, and Silurian the invertebrates were represented in all their subkingdoms by a varied fauna. The Elements of Geology It is, in fact, apparently impossible to draw any actual line of demarcation between the Upper Silurian and the overlying deposits of the Devonian or Old Red Sandstone series. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science The Silurian ocean swarms with these great shelled Cephalopods, of which the little Nautilus is now the only survivor. The Story of Evolution The gigantic Eurypterids of the Upper Silurian and Devonian are but feebly represented, and make their final exit here from the scene of life. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science The Silurian formations can be advantageously studied in the States of New York, Ohio, and other regions north and south of the great Canadian lakes. The Student's Elements of Geology The narrowing of the seas and the emergence of the lands which characterized the closing epoch of the Ordovician in eastern North America continue into the succeeding period of the Silurian. The Elements of Geology Both in Britain and in America the Lower Devonian beds repose with perfect conformity upon the highest Silurian beds, and the two formations appear to pass into one another by a gradual and imperceptible transition. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science The sharks and other large fishes, which have appeared in the Silurian, easily displace these clumsy and poor-mouthed competitors One almost thinks of the aeroplane superseding the navigable balloon. The Story of Evolution No one dare assert positively that the apparent first appearance of Fishes in the Upper Silurian is really their first introduction upon the earth: indeed, there is a strong probability against any such supposition. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science In all these countries there is an equally marked difference between the Cambrian fossils and those of the Upper and Lower Silurian rocks. The Student's Elements of Geology In the Ordovician and Silurian they are very plentiful, and at the close of the Silurian they pass out of existence, never to return. The Elements of Geology Lastly, the same distinguished observer has described from the Upper Silurian of North America the remains of the singular land-plants belonging to the genus Psilophyton, which will be referred to at greater length hereafter. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science The periods we have already covered—the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian—form the Primary or Palaeozoic Era, to which the earlier Archaean rocks were prefixed as a barren and less interesting introduction. The Story of Evolution The life of the Cambrian, though not so rich as in the succeeding Silurian period, nevertheless consists of representatives of most of the great classes of invertebrate animals. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science The third fauna agrees with the Upper Silurian of the same author. The Student's Elements of Geology The tracks and burrows of Annelides are as abundant in the Upper Silurian strata as in older deposits, and have just as commonly been regarded as plants. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science The Brachiopods continued to flourish during the Upper Silurian Period in immense numbers and under a greatly increased variety of forms. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science But the Silurian age closes with a fresh and very extensive emergence of the land, and this time it will have the most important consequences. The Story of Evolution In Wales, the line between the Cambrian and Lower Silurian is somewhat ill-defined, and is certainly not marked by any strong unconformity. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science About six species of Graptolite, a peculiar group of sertularian fossils before alluded to as being confined to Silurian rocks, occur in this shale. The Student's Elements of Geology Of these, the Lower Old Red Sandstone reposes with perfect conformity upon the highest beds of the Upper Silurian, the two formations being almost inseparably united by an intermediate series of "passage-beds." The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science These tubes are inhabited by a small Annelide, and structures of a similar character occur not uncommonly from the Upper Silurian upwards. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science It was assumed that some Cambrian or Silurian Annelid obtained this stiffening rod of cartilage. The Story of Evolution The exact parallelism of the Trenton and Cincinnati groups with the subdivisions of the Welsh Silurian series can hardly be stated positively. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Of fossils of this genus, which is very characteristic of the Lower Silurian, I shall again speak in the sequel. b. The Student's Elements of Geology The Trilobites, though still sufficiently abundant in some localites, have undergone a yet further diminution since the close of the Upper Silurian. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science In both America and Europe quite a number of generic types have survived from the Silurian, but few or no new ones make their appearance during this period Fig. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science The remains that we find make it probable that the fish left the water about the beginning of the Devonian or the end of the Silurian. The Story of Evolution Page 97 Of the life of the Lower Silurian period we have record in a vast number of fossils, showing that the seas of this period were abundantly furnished with living denizens. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science We now come to beds respecting the classification of which there has been much difference of opinion, and which in fact must be considered as beds of passage between Upper and Lower Silurian. The Student's Elements of Geology Taken as a whole, the Crustacean fauna of the Devonian period presents many alliances with that of the Upper Silurian, but has only slight relationships with that of the Lower Carboniferous. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science The mass of red and brown sandstone in these mountains is estimated at not less than 10,000 feet, clearly intercalated between the Carboniferous and Silurian strata. The Student's Elements of Geology This genus of brachiopoda was first found in Silurian strata, and is exclusively a palaeozoic form. The Student's Elements of Geology The Lower Silurian Corals, though the first of their class, and presenting certain peculiarities, may be regarded as essentially similar in nature to existing Corals. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science The predominance of bivalve mollusca of this peculiar class has caused the Silurian period to be sometimes styled "the age of brachiopods." The Student's Elements of Geology These beds, therefore, now generally called the "Downton Sandstone," are classed as the newest member of the Upper Silurian. The Student's Elements of Geology I therefore prefer to regard them as the base of the Upper Silurian, to which group they are linked by more than twice as many species as to the Lower Silurian. The Student's Elements of Geology Nothing is more remarkable in these beds, and in the Silurian strata generally of all countries, than the preponderance of brachiopoda over other forms of mollusca. The Student's Elements of Geology In the general details of their structure, the Lower Silurian Corals do not differ from the ordinary Corals of the present day. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Keilhau, Professor, on granite veins. —, on planes of foliation. —, on Silurian granite of Norway. —, on protrusion of granite. The Student's Elements of Geology In this reform they were aided by a suggestion of Mr. Lonsdale, who, after studying the Devonshire fossils, perceived that they belonged to a peculiar palaeontological type of intermediate character between the Carboniferous and Silurian. The Student's Elements of Geology Among the 18 species of all classes enumerated by Mr. Etheridge, two-thirds are common to the Middle Devonian, but only one, the ubiquitous Atrypa reticularis, can with certainty be identified with Silurian species. The Student's Elements of Geology Table 26.1 will explain the two principal divisions, Upper and Lower, of the Silurian rocks, and the minor subdivisions usually adopted, comprehending all the strata originally embraced in the Silurian system by Sir Roderick Murchison. The Student's Elements of Geology The Crinoids, though in some places extremely numerous, have not the varied development that they possess in the Upper Silurian, in connection with which their structure will be more fully spoken of. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Silurian, derivation of the name. —, granite of Norway. —, metamorphic, of North Highlands. — rocks, classification of. — strata of the continent of Europe. — strata of United States. — volcanic rocks. The Student's Elements of Geology The genus is still better known as a Silurian form, but the spinose species appear to belong exclusively to the "Lower Devonian," and are found in Britain, Europe, and the Cape of Good Hope. The Student's Elements of Geology It consists of brownish and yellow sandstones with calcareous nodules, having sometimes a conglomerate at the base derived from the waste of the Lower Silurian rocks. The Student's Elements of Geology These May-Hill beds were formerly supposed to be part of the Caradoc formation, but their true position was determined by Professor Sedgwick to be at the base of the Upper Silurian proper. The Student's Elements of Geology More important, however, than any of these are the Trilobites, which may be considered as attaining their maximum development in the Lower Silurian. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Sharpe, Mr. D., on American Silurian fossils. —, on fossils distorted by cleavage. The Student's Elements of Geology Thus, in Norway and Sweden, the total thickness of strata of Silurian age is considerably less than 1000 feet, although the representatives both of the Upper and Lower Silurian of England are not wanting there. The Student's Elements of Geology In parts of the globe still more remote from Europe the Silurian strata have also been recognised, as in South America, Australia, and India. The Student's Elements of Geology They consisted chiefly of trilobites of genera distinct from those occurring in the overlying Silurian formations. The Student's Elements of Geology Almost every subdivision of the Lower Silurian series has its own special and characteristic species of Trilobites; and the study of these is therefore of great importance to the geologist. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science This fossil, referred, though somewhat doubtfully, to a form of hydrozoid or sertularian polyp, has not yet been met with in strata above the Silurian. The Student's Elements of Geology The second fauna tallies with Murchison's Lower Silurian, as originally defined by him when no fossils had been discovered below the Stiper-Stones. The Student's Elements of Geology The Tertiary strata of that age are seen on both sides of the Rhine, in the neighbourhood of Bonn, resting unconformably on highly inclined and vertical strata of Silurian and Devonian rocks. The Student's Elements of Geology Section in Lower Silurian slates of Cardiganshire, showing the cleavage planes bent along the junction of the beds. The Student's Elements of Geology No trace of the true Cuttle-fishes has yet been found in Lower Silurian deposits; but the Tetrabranchiate group is represented by a great number of forms, sometimes of great size. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science But, although the species are distinct, the genera are the same as those which characterise the Silurian rocks above, and none of the characteristic primordial or Cambrian forms, presently to be mentioned, are intermixed. The Student's Elements of Geology In these ancient grits no fossils have been found, but they are supposed to be of Cambrian date, for Sir R. Murchison found Lower Silurian strata resting unconformably upon them. The Student's Elements of Geology Trenton limestone, and other Lower Silurian groups of North America. The Student's Elements of Geology Metamorphic Strata of older date than the Silurian and Cambrian Rocks. The Student's Elements of Geology It need only be added in this connection that the Lower Silurian rocks have yielded the remains of many other Tetrabranchiate Cephalopods besides Orthoceras. The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science |
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