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ORIGIN OF THE CHOUTEAU FAUNA 289 
boniferous* and Hall? includes that genus as a synonym under 
Euomphalus, which is abundantly represented in the European 
Devonian fauna. 
The genus Loxonema is as old as the Ordovician and the 
species are all so much alike in their general habit and varia- 
tions that in order to trace the origin of any particular Carbon- 
iferous species, it would be necessary to show that it possessed 
some distinctive mark found in the species of some particular 
Devonian province and absent from the representatives of 
the genus of all other Devonian faunas. Thus we are led, by 
a critical review of both the genera and species, of which an 
origin from outside the Mississippi province of Devonian time is 
suspected, to the conviction that there is no positive evidence 
of such a course. On the other hand there seems to be no rea- 
son to doubt the natural succession of the Chouteau fauna from 
the Devonian fauna already in the province. 
Although there seems to be little or no evidence that the 
Chouteau fauna was not all derived from one common source, it 
is not impossible that there may be traces of species which 
were not descended from any Devonian species of Europe. If 
the evidence brought forward in the paper on the Cuboides 
zone will bear the interpretation put upon it, there was such a 
mingling of two quite distinct faunas at the opening of the 
Chemung period in the New York area. There are no facts 
known to me to prevent the supposition that the Chouteau 
fauna may have species derived from the older fauna, but Mr. 
Weller does not mention any such facts, and I am not aware 
that there are any. 
If it could be shown that the Chouteau fauna was of the 
same age as the base of the Chemung, it might be inferred that 
the mingling of faunas from different sources, which is supposed 
to have taken place in the New York region, affected also the 
faunas in the Ozark region of Missouri; but if the Chouteau is 
later than the Chemung, as I believe was the case, then the 
*Handbuch der Palzontologie, II., p. 207. 
? Paleontology, New York, Vol. V., Part II., Text, p. 54. 
