The general conclusions of the brothers Ameghino in reference to the geology of Patagonia, as detailed in the foregoing valuable synopsis of results, may be still more briefly stated in the following manner

(1) The oldest sedimentary rocks in which fossils have been found are red sandstones, containing mineralized wood, Dinosaurian bones, and other smaller reptilian remains. “Upper Cretaceous.”

(2) The terrestrial or fresh-water Pyrotherium Beds succeed these and may be partly intercalated with them. They contain a singular mammalian fauna, notably primitive Ungulata. “Upper Cretaceous.”