Walcott was the first geologist to identify pre-Cambrian fossil bacteria from microscopic examination of thin rock slices. 沃尔科特是第一个在岩石薄片镜检中鉴定出前寒武纪化石细菌的地质学家。
Geologists would also call it extrusive rock because it solidified on the Earth's surface. 因为它是喷出地球表面凝固而成，地质学家也称它为喷出岩。
