CENOZOIC HISTORY OF WIND RIVER MOUNTAINS 159 
follows that the long period of terracing which has been described, 
in which plains 4, 3, 2, and 1 were successively formed, is all 
to be placed before the time of the earlier glaciation. It may 
be that there were still earlier glaciations in the Wind River 
Range but if there were they have not been recognized, and 
for the present practically all of the higher terraces may be 
assigned to the Tertiary. 
