Chap. Ill GEOGRAPHICAL DISTRIBUTION. " 299 



faunoe of the temperate and arctic zones : for enough is ah-eacly known of the 

 geographical tlistribution of animals to make it certain, that the inhabitants of 

 tropical America, of tropical Africa, of tropical Asia, and of tropical Australia, belong 

 to different faunte, as well as those of the temperate zones of these continents, 

 and of the oceans bathing their shores. 



Again, when palaeontologists speak of a Silurian founa, a Devonian fauna, a 

 Carl^onifei'ous tauna, a Jurassic founa, etc., they either prejudge questions which are 

 tar from being settled, or, if aware of the difficulties involved in their nomenclature, 

 allow themselves to use this term still more vaguely than zoologists do. In the 

 first place, neither the Silurian nor the Jurassic era, nor any other of the long 

 eras generally designated by geologists as geological formations, wms inhabited from 

 its beginning to its end by the same kinds of animals. Taking, for instance, the 

 Silurian series, within the narrow limits of the State of New York, or the Oolitic 

 series within the limits of the Jura, or the Cretaceous series within the limits of 

 central Europe, we find in each of these series a succession of difterent species, 

 comliined in such a manner as to form a succession of fauna^, the natural geo- 

 graphical boundaries of which may be left out of consideration in view of our 

 present object, but constituting as truly distinct faunte as the animals living along 

 the Atlantic shores of the southern United States constitute a different fauna from 

 those of the Mediterranean. Here, then, we have, in course of time and within 

 the same boundaries, a succession of faunte, bearing to one another relations similar 

 to those existing between faunaj of the present period within different bovmdaries ; 

 showing the impropriety of applying the name of fauna; to the organic remains 

 found in these different series, and of using it at the same time for the zoological 

 IDrovinces, as denned by zoologists, for the animals now living. The matter is not 

 improved by limiting the term faunae to shorter geological periods. No doubt the 

 fossils found together by Barraude in the lowest fossiliferous beds of Bohemia repre- 

 sent the first fauna of that region. But the " faune premiere," if it means any 

 thing, must mean the oldest fauna extending over an area, not yet fully defined 

 perhaps, including the first organisms only that lived upon earth in the geographical 

 area now called Bohemia. It cannot at the same time mean any other combi- 

 nation of more or less closely allied species, Uving at the same jjeriod, in other 

 parts of the world ; unless it be at the same time shown, that, in these earlier 

 ages of the world's history, there were no faunal difTerences among animals. 

 Enough, however, is already known of these primeval inhabitants of our glo];)e to 

 leave no doubt, that, though the differences in their geographical range may not 

 everywhere be so striking as. they are now, they nevertheless differed in difierent 

 parts of its surface ; so that, to extend the expression of " faune premiere " to all 

 the inhabitants of the globe belonging to the ideological ao-e of the lower Silurian 



