PREVIOUS TO THE LAST GEOLOGICAL REVOLUTION. 377 



divisions, of which the first contains those animals that con- 

 siderably differ from all now living, while the second includes 

 such as resemble the present order of creation. Before, 

 however, I proceed to distinguish these fossil species, I must 

 first put aside those of which I either possess too imperfect 

 specimens to allow me to institute any satisfactory compari- 

 son, or else the osteology of the correspondent recent species 

 is not sufficiently known to me. To this class belong seven 

 species, namely, Tapir, Cervus, the small species of Tiger, 

 Fox, Coata-mundi, and the lesser kind of Capivar. I do 

 not add to this list either the species of Mtis or Didel- 

 phis. Not because I want the necessary materials for 

 comparison, but because a complete comparison of these 

 species requires lengthened and accurate previous exami- 

 nation of the osteology of the recent kinds, a labour to 

 which I have not as yet had the opportunity of devoting 

 myself. Taking away these eleven species, there remain forty- 

 three, which will serve for the foundation of our comparison. 

 I begin with the species of the four genera. Camel, Antelope, 

 Bear, and Hycena', which, as we have seen, are indeed not now 

 found in the Highlands of Brazil, but have not ceased to con- 

 tinue their existence in other parts of our earth. We have 

 before observed that the two species of the genus Camel ex- 

 cluded, by their very size, any suspicion of their conformity 

 with the existing species of this genus. With regard to the 

 three other genera, Bear, Antelope, and Hycena, nothing but 

 direct comparison can positively decide the question as to 

 their identity with the respective species inhabiting the chain 

 of the Andes, and the Old World ; at the same time I cannot 

 but think that the result of the investigations I am about to 

 detail will leave little room for doubt on this subject. In 

 order, however, to remove all uncertainty from the compari- 

 son I am instituting, I will cast out these three also, so that 

 only forty species remain to be considered. In the first di- 

 vision, which comprises all those species which differ con- 

 siderably from those now living here, we may first of all class 

 all those that belong to genera that have entirely disappeared 

 from the earth's surface. These, as we have seen, are the 

 following ten : Euryodon, Heterodon, Chlamydotherium, 

 Hoplophorus, Pachytheriimi, Ccelodon, Megalonyx, Lep- 

 totherium, Mastodoii, and Protopithecus : these genera com- 

 prise fourteen species ; to which we may add the undeter- 

 mined genus of Rodent, with a single species,and the lately 

 mentioned species of Camel; in all seventeen species. 



I now come to the genera that are now, as formerly, found 

 in this district, excluding those species which either the first 



Vol. IV.~No. 44. n. s. 3 a 



