The older the layers, the more each of them is uniform over a great extent; the newer the layers, the more they are limited and subject to variation within small distances.

The appearance of the bones of quadrupeds, especially those of complete bodies in the strata, tells us either that the layer itself which carries them was in earlier times dry land or that dry land was at least formed in the immediate area.

The lowest and most level land areas show us, especially when we dig there to very great depths, nothing but horizontal layers of material more or less varied, which almost all contain innumerable products of the sea.

Georges Cuvier Quotes