- GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of Geology Exclusive of North America, Geological Society of America, Boulder, CO, United States
"The similarity of the minerals (both in variety and abundance) of the newer and older formations does not only prove that both were derived from the same source-rocks and that the 'pre-Cambrian' of the southern countries was already uncovered in Neolithic times [Quaternary]. . . , but also that . . . the greater part of the Nile sediments were carried by tributaries draining the Abyssinian Plateau as is the case at the present day."