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in the earth, and which must have once lived upon its sur- 

 face, that the Geologist has discovered that the crust of 

 this globe must have undergone very great changes in the 

 course of ages, and that it must have exhibited many a 

 rich and varied surface, crowded with animated inhabit- 

 ants, long anterior to the existence of the busy scene we 

 now contemplate and enjoy. Anterior to the formation of 

 the transition rocks, there appear to have been no animals 

 upon this earth ; and during the formation of all the tran- 

 sition and secondary strata, the animals that existed were 

 almost all marine, which shows that these strata were 

 mostly of marine origin, and that animal life originated 

 and was developed in the bosom of the deep. Besides 

 pointing out the order of succession in the formation of the 

 strata, and their mode of formation by quiet deposition 

 from a fluid, which alone could have preserved the delicate 

 structure of the enclosed relics, these remains of animals 

 show what must have been the nature of the situation 

 where we now find them, at the period of their deposition ; 

 whether it formed the bottom of a fresh-water lake, or the 

 submerged surface of a peopled continent, or the bed of a 

 primeval sea ; and many strata of the earth are character- 

 ized by the particular species of fossil animals they contain. 

 By thus pointing out the extensive and terrible catastro- 

 phes to which the Animal Kingdom has often been subject- 

 ed, we are enabled to perceive a cause of the many ap- 

 parent interruptions in the chain of existing species. 



As the knowledge of Mountain Rocks is founded on an 

 accurate acquaintance with the characters and properties 

 of simple Minerals, the study of Mineralogy is intimately 

 connected with that of Organic Remains, and a previous 

 acquaintance with the practical details of this branch of 

 Natural History will greatly facilitate the most intricate 

 and obscure paths of the Zoologist. He is often unable to 

 obtain any information as to the locality or the geological 

 situation of the fossil animals presented to his inspection, 

 and must judge from the nature of the enveloping mass or 



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