598 The American Naturalist. [June, 
debris mixed with fragments of limestone and wood. In my opinion 
all of these caves have been submerged, and their contained deposits 
are rearranged sediments. The later caves have not been submerged 
since they received their present contents. The difference in the age 
of the respective deposits is, then, considerable. In the case of the 
Lookout Cave, Tennessee, explored by Mr. Mercer, a part of the old 
cave deposit remained, and was covered by the modern bed. 
Geologic history presents us with a submergence at the middle of the 
Plistocene period, precisely such as constitutes the culminating point 
of every geologic system. This has been termed by Dana the Cham- 
plain epoch, and we may well retain the name in a broadened sense for 
the continental submergence to which we owe not only the Champlain 
and Erie formations of the North, but the Columbia gravels of the 
Middle and Southern States, so thoroughly studied by McGee. That 
the submergence was not without short reversed movements and oscil- 
lations has been shown by Spencer, but that it was continental in extent 
there can be no doubt. It is also clear that it was followed by an 
emergence, which constitutesthe Terrace epoch of Dana’s system. We 
are then led to the conclusion that the fauna of the Megalonyx epoch 
is pre-Champlain, and that of the later caves post-Champlain. The 
country was, however, not probably wholly submerged. Some species, 
mostly the smaller ones, and the genus Megalonyx, survived on the not 
submerged land, and these we find to be common to the two faunas. The 
Hartman’s cave, within the limit of the ice sheet, is on a hill now 
elevated 800 feet above the level of the Delaware River. That it was 
subjected to submergence is shown by the stratified clay with which 
it is even now partly filled. Its fauna does not include all the types 
of the Megalonyx fauna, and does include the Castoroides, as shown 
by Leidy. It includes a larger proportion of existing species than the 
usual Megalonyx fauna. Its peculiarities are probably due to its 
northern latitude. 
This submergence corresponds with the one which Professor Prest- 
wich insists effected Europe subsequent to the glacial elevation.’ The 
Paleolithic flints of Kent he thinks demonstrate such a submergence, 
and his reasoning as to the tharacter of the deposits in the European 
caves applies exactly to the bone breccias of the Megalonyx age of our 
caves here. 
The existence of Paleolithic man in North America has not yet been 
demonstrated by the cave explorations so far as they have gone. We 
can, however, only consider this conclusion as one which may be re- 
*Transac. Royal Soc. London, 1893, p. 903. 
