Basilosaurus (or Zeuglodon) bones are found only in the Jackson marls, and other marine fossils are abundant.
Fraas, of Stuttgart, has demonstrated the derivation of the whale-like Zeuglodon from the creodonts.
Andrews has, moreover, not only brought forward additional evidence in favour of this most remarkable line of descent, but is confident - which Professor Fraas was not - that Zeuglodon itself is an ancestral cetacean, and consequently that whales are the highly modified descendants of creodonts.
It must be admitted, however, that the links between Zeuglodon and typical cetaceans are at present unknown; but it may be hoped that these will be eventually brought to light from the deposits of the Mokattam Range, near Cairo.