332 AXXUAL OF SCIENTIFIC DISCOVERY. 



with the modern whale, of a hundred feet in length. During the period in 

 which we htivc proof that Cctacca have existed, the cvi '.L-.ICC ia the shnpe 

 of bones and teeth which latter enduring characteristics in most of the spe- 

 cies arc peculiar for their great number in the same individual must have 

 been abundantly deposited at the bottom of the sea; and as cachalots, 

 grampuses, dolphins, and porpoises, arc seen gambolling in shoals in deep 

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

 dences of vertebrate life in the strata now in course of formation at the 

 bottom of such oceans. Accordingly, it consists with the known character- 

 istics of the Cetacean class to find the marine deposits which fell from seas 

 tenanted, as now, with vertebrates of that high grade, containing the fossil 

 evidences of the order in vast abundance. The red crag of our eastern 

 counties contains petrified fragments of the skeletons and teeth of various 

 Cetacea, in such quantities 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 evidence of Cetacea in cretaceous beds seems 

 to indicate a similar period for their beginning as for the soft-scaled cycloid 

 and ctenoid fishes which have superseded the ganoid orders of mcsozoic 

 times. 



"\Ve cannot doubt but that, had the genera Ichthyosaurus, Pliosaurus, or 

 Plesiosaurus, been represented by species in the same ocean that was tem- 

 pested 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 

 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 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 mesozoic epochs, the evidence of vertebrates governing the 

 ocean, and preying on inferior marine vertebrates, is as abundant as that 

 of air-breathing vertebrates in 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 Croco- 

 dilia, played the same part, and fulfilled similar offices, in the seas from 

 which the lias and oolites were precipitated, as the Delphinidre and Bala> 

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

 monuments or trustworthy recordsof 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 contrasted, it is 

 against the doctrine of the Uniformitarians. Organic remains, traced from 

 their earliest known graves, are succeeded, one series by another, to the 

 present period, and never reappear when once lost sight of in the ascending 

 search. As well might we expect a living Ichthyosaur in the Pacific, as a 

 fossil whale in the Lias. The rule governs as strongly in the retrospect as 

 the prospect. And not only as respects the Yertebrata, but the sum of the 

 animal species at each successive geological period has been distinct and 

 peculiar to such period. Xot that the extinction of such forms or species 

 Avas sudden or simultaneous: the evidences so interpreted have been but 



