PALEONTOLOGY 137 



which are the uppermost division of the Eocene. 

 This is a remarkable fact when we remember that 

 the older divisions of the Eocene are well represented 

 along the Gulf-border region, as is also the Creta- 

 ceous. Le Conte says: " No intermediate links have 

 yet been found connecting this with other orders of 

 mammals, or with the great reptiles. And yet from 

 their large size and marine habits, they are more 

 likely than land mammals to have been found if they 

 existed in the earlier Eocene or Cretaceous times."* 



That the remains of whales are likely to be pre- 

 served, is shown by the abundance of their remains in 

 the Miocene. Dana says:. "The Miocene of the Atlan- 

 tic border has afforded remains of many Cetaceans. 

 Among them are various Dolphins, several species of 

 Whales of the genus Squalodon, related in teeth to 

 the Zeuglodon, the largest about 30 feet long. Others 

 having the teeth excessive in number, or multiplicate, 

 and provided with only one root; others having simi- 

 lar teeth, but only in the upper jaw, as in the genus 

 Physeter, or that including the Sperm Whale; others 

 with teeth in neither jaw, as the Baleen, or Whale- 

 hone Whales, but having several hundred plates of the 

 so-called whale-bone growing vertically downward 

 from above, "t 



It is no adequate answer to this to say that in the 

 Cretaceous and other periods there are rock deposits 

 that are quite destitute of fossils of any kind. The 

 force of the objection in this and similar cases is that 

 the remains of the Zeuglodon and other Eocene 

 mammals are absent from rocks abounding in verte- 

 brate fossils, in which, if they lived while these rocks 

 were being deposited, their remains would be pre- 

 served. 



It is claimed that the fossil remains of certain 



* Elements of Geology, p. 523. t Manual of Geology.p. 912. 



