394 S. W. WILLISTON 
perhaps, but with marked modifications in structure peculiar to the 
American forms which separate them widely from their Permian 
relatives of Europe. ‘The third, representing the earliest known type 
of the modern amphibians (Lysorophus), is, so far, entirely peculiar 
to our Permian, another evidence of isolated evolution. ‘There are 
no known representatives of the stereospondylous types of Stegocepha- 
lia, that is the true labyrinthodonts, which, however, as we shall see, 
suddenly reappear in the Upper Trias, and doubtless were represented 
in the later Pennsylvanian of this country by known forms from 
Kansas, and by Marsh’s Eosaurus from Nova Scotia, etc. Upon the 
whole, then, our Permian fauna is sharply and almost completely 
distinguished from any supposed contemporaneous or indeed any 
fauna known elsewhere, and may have been evolved wholly in America 
from known Pennsylvanian forebears. The Texas and Oklahoma 
Permian deposits were undoubtedly for the most part or entirely 
those derived from extensive flats of slight elevation, deposits com- 
posed for the most part of the finest, almost impalpable mud, with 
little extraneous material, traversed here and there by current channels, 
and streams which have left for evidence interrupted ribbons of fine 
or coarse sandstone, and some beds of gravel, with intercalations 
everywhere of lenticular masses of very fine sandstone of aeolian or 
quiet water origin. In other words, as has often been said, the depos- 
its are typical shallow freshwater deposits, gradually merging on the 
north, as Beede has recently shown, into the shallow marine deposits 
of the Lower Kansas Permian. Few if any real marine vertebrates 
are known from all these extensive and varied deposits, since the 
shark and dipnoan remains not infrequently found may have been, 
and doubtless were, of fishes already habituated to fresh or brackish 
water. That there may have been in America contemporaneous 
forms living on the higher lands of which we have yet no knowledge 
is doubtless true, but not very probable; the higher grounds of the 
Wichita Mountains on the north have sent abundant gravel and sand 
material southward into these deposits, and they surely would also 
have sent some fragments of distinctive high-land creatures with 
them had there been any. There is, I believe, in all these deposits, 
not a single hint of the ancestry of modern reptiles save possibly of 
the turtles and ichthyosaurs. Nor do I believe that there is any evi- 
