494 TLE J OOTIN ALN ORMGIROIEO Ge 
reality this should be subject to much greater limitations than 
even the ideas of homotaxis, as formulated by Huxley,’ would 
demand. ‘ 
Faunas need not and do not appear at the same horizon, nor 
even in the same order of succession, all over the world, for an 
intermigration between two distant localities would produce an 
apparent inversion of the two faunas at either place. 
The genus Clymenta, according to Professor J. M. Clarke,” 
appears in the Gonzatites intumescens beds of New York ; in Europe 
Clymenta is wholly unknown in the Znxtumescens fauna, but is the 
characteristic form of the next higher division of the Devonian, 
where the /ntwmescens fauna is already extinct. 
In the Upper Trias, Karnic stage, of California, Rhabdoceras 
and Hlalorites occur, although Rhabdoceras is known in the Alps 
only from the higher Jura stage, and Halorites in both Alps and 
Himalayas ts characteristic of the latter horizon. Also in the 
Hosselkus limestone, Upper Trias, of Shasta county, California, 
Trachyceras and Protrachyceras occur, in the zone of Tvopites sub- 
bullatus, and associated in the same rocks with a characteristic 
Subbullatus fauna ; but inthe Alps and in the Himalayas Tvachyceras 
and Protrachyceras are older than: the Swdbullatus fauna, and 
never occur in the same beds with it. The question then remains, 
Did Trachyceras and Protrachyceras survive longer in America than 
in Asia and Europe, or did the Swbéullatus fauna reach here 
earlier? The researches of Mojsisovics3 show that 7vopites is 
probably indigenous to the Arctic-Pacific Triassic province, and 
that Zrachyceras is endemic in the Mediterranean region. ) 
Fleterochthonous* faunas.—In many cases faunas appear unher- 
alded by local ancestors, having been brought in by migration 
from other regions. 
Thus in America, according to Professor H. S. Williams,5 the 
* Quart. Jour. Geol. Soc. XVIII., 1862, 46. 
2Am. Jour. (Sci. LiL.) Ser, Vol. Xcel 57. 
3Arktische Triasfaunen, p. 148 and Abhandl. K. K. Geol. Reichsanstalt Wien... 
. VI, Part II., Second half, p. 7. : 
4 From €repos, other, and xOwv, land. 
SCuboides Zone and its Fauna. Bull. Geol. Soc. Am., Vol. I. 
Vo 
a 
