59 



In all cetacea the skeleton is well ossified, and the vertebrae 

 are very numerous : the smallest cetaceans would be deemed large 

 amongst land-mammals j the largest surpass in bulk any creatures 

 of which we have yet gained cognizance : the hugest ichthyosaur, 

 iguanodon, megalosaur, mammoth, or rnegathere, is a dwarf in com- 

 parison with the modern whale of a hundred feet in length. 



During the period in which we have proof that Cetacea have 

 existed, the evidence in the shape of bones and teeth, which latter 

 enduring characteristics in most of the species are peculiar for their 

 great number in the same individual, imist have been abundantly 

 deposited at the bottom of the sea; and as cachalots, grampuses, 

 dolphins, and porpoises are seen gambolling in shoals in deep 

 oceans, far from land, their remains will form the most charac- 

 teristic evidences of vertebrate life in the strata now in course of 

 formation at the bottom of such oceans. Accordingly, it consists 

 with the known characteristics of the cetacean class to find the 

 marine deposits which fell from seas tenanted, as now, with verte- 

 brates of that high grade, containing the fossil evidences of the 

 order in vast abundance. 



The red crag of our eastern comities contains petrified frag- 

 ments of the skeletons and teeth of various Cetacea, in such quanti- 

 ties as to constitute a great part of that source of phosphate of lime 

 for which the red crag is worked for the manufacture of artificial 

 manure. The scanty and dubious evidence of Cetacea in newer 

 secondary beds 1 seems to indicate a similar period for their begin- 

 ning as for the soft-scaled cycloid and ctenoid fishes which have 

 superseded the ganoid orders of mesozoic times. 



We cannot doubt but that had the genera Ichthyosaurus, Plio- 

 saurus, or Plesiosaurus, been represented by species in the same 

 ocean that was tempested by the Balrenodons and Dioplodons of 

 the miocene age, the bones and teeth of those marine reptiles 

 would have testified to their existence as abundantly as they do at 

 a previous epoch in the earth's history. But no fossil relic of an 

 enaliosaur has been found in tertiary strata, and no living enalio- 

 saur has been detected in the present seas : and they are conse- 

 quently held by competent naturalists to be extinct. 



In like manner does such negative evidence weigh with me in 

 proof of the non-existence of marine mammals in the liassic and 

 oolitic times. In the marine deposits of those secondary or meso- 



1 See 'Introduction' to Owen's History of British Fossil Mammalia, 8vo., 

 1846, p. xv. 



