THE PRE-ADAMITE EARTH. 



means already explained, in the strata of England, Sweden, and 

 Russia, and in those of the State of New York. The organic 

 deposits show that, like the present seas, they were inhahited by 

 the various classes of marine animals which are peculiar, some to 

 shores within the play of the tides, others to littoral regions more 

 removed, and others to the great depths of the ocean. 



261. The only Vertebrate animals of this period which have 

 left their traces are some placoid fishes, which belong to the family 

 of Cestracions, of which the shark presents a living example. Of 

 articulated animals there lived a great number of Trilobites 

 (fig. 6, 62), an order which at a period a little later became 

 extinct. The forms of life, however, which most abounded 

 belonged to the Molluscous and Radiated divisions. Tentaculi- 

 ferous cephalopods swarmed in the seas, the genera of some of 

 which did not survive the period, and those of many disappeared 

 before the close of the Palaeozoic age. 



Molluscous brachiopods, marine gastropods, lamellibranchia 

 (oyster and mussel), and bryozoa, existed in numbers more or 

 less considerable. 



Of the Radiata there prevailed cchinodermata, asteroids, and 

 numerous crinoids, a great number of polyparia or zoophytes, and 

 some amorphozoa. 



262. The remains of vegetation consist chiefly of some marine 

 plants peculiar to the State of New York, described and figured by 

 Mr. Hall. Coal of this epoch, which can only consist of vegetable 

 remains, is worked at Vallongo in Portugal. 



The remains of vegetation, as well as the visual organs of 

 animals, show that light and air existed then as now. We have 

 already noticed the structure of the eyes of Trilobites, and shown 

 their analogy to those of insects and other Annulata. 



263. It is certain, that not only at this first period, but at all 

 succeeding periods, until that which immediately preceded the 

 present creation, the heat proceeding from the interior pre- 

 dominated over the influence of solar radiation, in a sufficient 

 degree to efface all isothermal lines, and to equalise the climate at 

 all latitudes from the equator to the poles. Proofs of this will 

 appear in the analysis of the fauna and flora of all the stages, 

 since the same tropical genera and families will be found de- 

 posited in the strata at the line and within the; polar circle, as 

 well as at all intermediate latitudes. 



264. In this first period no terrestrial animals existed, although 

 the land was clothed with a luxurious vegetation; at least no 

 remains of such are found. The perishable nature of the insects, 

 and many other Annulata, might have caused their disappearance ; 

 but, notwithstanding this, traces of such tribes are found in later 



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