Since the fossil record in sedimentary rocks of the earth’s crust supposedly provides documentary evidence of organic evolution throughout geologic time, it is of considerable importance to know how these fossil-bearing sediments were originally deposited. A study of these phenomena in light of modern knowledge of sediment hydraulics and fluid mechanics indicates that the sediments must have been laid down very rapidly, even catastrophically, rather than slowly over long ages. Furthermore, the evidence favors one single major depositional epoch rather than a large number of individual and localized sedimentary catastrophes spread over great expanses of time.