241 



Prof. Agassiz made a communication on consecutive 

 faunae and their corresponding number of geological for- 

 mations, as furnishing arguments against the theory of 

 Darwin. 



He believed that the number was considerably greater than had 

 been hitherto admitted. He objected to the use made of the 

 great and well-known changes in animals under the influence of 

 domestication, as an argument in favor of similar probable changes 

 in geological ages ; the genera of these domesticated animals, as 

 hos, canis, &c., lived ages before the human period, but their re- 

 mains show no such changes as now occur ; these are two distinct 

 series of facts, and are not comparable. The representatives of 

 these fauna3 differ specifically, and do not pass from one to the 

 other, and this is true from, the most ancient to the most recent 

 periods. He defined faunae as groups of animals enclosed within 

 circumscribed areas ; there are many of these on the globe, and 

 they must not be confounded with zoological realms ; of the latter, 

 New Holland may be mentioned as an example, having animals 

 of a peculiar type ; so are the East Indies, Africa south of the 

 Atlas Mountains, America from the sub-arctic regions to Patagonia, 

 and the arctic regions themselves. Faunae, on the other hand, 

 occupy more limited provinces characterized by species related 

 to each other, as they are more largely in realms. Faunje differ 

 in various parts of the world, and no one can be taken as a type 

 of existing creation ; for instance, the fauna of Canada differs en- 

 tirely from that of Africa, and any zoologist who should take one 

 or the other or any single fauna as the type of the world's ani- 

 mals would commit an absurdity ; yet geologists do this con- 

 stantly in their identifications of geological periods, and of course 

 fall into the gravest errors. He found fault with the methods of 

 determining the limits of successive faunas usually pursued by 

 geologists ; he thought that this order should be determined by 

 the fossils ; that the rocks should be regarded merely as the 

 tombs of the fossils, that naturalists should try to find out the ani- 

 mals of an epoch, and establish the limits of faunae on zoological 

 and not on physical principles. He made use of the strata of 

 New York State, as being well ascertained, in his determinations 

 of the primary groups of faunae. The lower and upper Silurian 



PROCEEDINGS B. S. N. H. VOL. VII. 16 MAY, 1860. 



