The glacial erosion of most of the Shasta lavas produces detritus, composed of rough, sub-angular boulders of moderate size and of porous gravel and sand, which yields freely to the transporting power of running water.

大部分 Shasta 熔岩的冰川侵蚀产生碎屑，由中等大小的粗糙、亚角巨石和多孔砾石和沙子组成，自由地屈服于流水的输送能力。

They turned to Antarctica because, not only was it reached only 200 years ago, but it also supports a variety of processes, including glacial erosion, frost cleaving and river transport, which might batter rocks into tool-like shapes.

他们转向南极洲， 因为它不仅在 200 年前才到达，而且还支持多种过程，包括冰川侵蚀、霜裂和河流运输，这些过程可能会将岩石打造成类似工具的形状。