Another passage from Henry Fairfield Osborn, “Hunting the ancestral elephant in the Fayûm desert”:
As we ascended, we noted suddenly the entire disappearance of the sea-shells, adn entered purely freshwater desposits, where the land-filling process gained supremacy. We climbed tier above tier, and finally reached the great, partly level, partly rolling, platform stretching off in each direction as far as the eye could reach. Here we saw the sandy delta deposits of a river system which was much older than the Nile.
This was our destination.
We slowly recognized this as the level on which all our explorations were to be made. The giant trunks of fossilized trees began to appear -- trees that were borne down the rivers from the great forests of the south, their petrified trunks, from thirty to seventy feet in length, protruding from the sand, which was an auspicious sign of the proximity of the remains of quadrupeds, for both were washed down together. Remains of crocodiles, also, and of great turtles, began to be seen, and we were convinced that we were in the very fossil-bearing tier itself.
I will note an impression I had while reading the article, that it’s very interesting to see how paleontologists dealt with certain issues in the time before acceptance of continental drift. The passage immediately before the one quoted here dealt with the “northward growth” of Africa into the Mediterranean, from the Fayum to the present coast, entirely as a process of river discharge.
Osborn HF. 1907. Hunting the ancestral elephant in the Fayûm desert: Discoveries of the recent African expedition of the American Museum of Natural History. The Century Magazine 74(6):815-835.