4J0 PALEONTOLOGY 



same ocean that was tempested by the Bakenodons and Dio- 

 plodons of the miocene age, the bones and teeth of those 

 marine reptiles would have testified to their existence as abun- 

 dantly 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 enaliosaur has been detected in the 

 present seas : and they are consequently held by competent 

 naturalists to be extinct. 



In like manner does such negative evidence testify to the 

 non-existence of marine mammals in the liassic and oolitic 

 times. In the marine deposits of those secondary or mesozoic 

 epochs, the evidence of vertebrates governing the ocean, and 

 preying on inferior marine vertebrates, is as abundant as that 

 of air-breathing vertebrates hi the tertiary strata ; but in the 

 one the fossils are exclusively of the cold-blooded reptilian 

 class, in the other, of the warm-blooded mammalian class. The 

 Enaliosauria, Cetiosauria, and Crococlilia, played the same part 

 and fulfilled similar offices in the seas from which the lias 

 and oolites were precipitated, as the BelpMnidm and Balccnidcc 

 did in the tertiary seas, and still do in the present ocean. 

 The unbiassed conclusion from both negative and positive 

 evidence in this matter is, that the Cetacea succeeded and 

 superseded the Enaliosauria. To the mind that will not 

 accept such conclusion, the stratified oolitic rocks must cease 

 to be trustworthy records of the condition of life on the earth 

 at that period. 



So far, however, as any general conclusion can be deduced 

 from the large sum of evidence above referred to, and con- 

 trasted, it is against the doctrine of the Uniformitarian. 

 Organic remains, traced from their earliest known graves, are 

 succeeded, one series by another, to the present period, and 

 never re-appcar when once lost sight of in the ascending 

 search. As well might we expect a living lehthyosaur in the 

 Pacific, as a fossil whale in the Lias: the rule governs as 



