238 W. M. Fontaine—Mesowiec Strata of Virginia. 
formation of glaciers. Along with a sufficient degree of 
cold we must have abundance of moisture to produce glaciers. 
This would be supplied by the western and southwestern 
winds. The latter would sweep unchecked from the Pacific 
over vast bodies of warm waters in the interior, and meeting 
Oolitic flora. Many of the features seen here resemble those of 
the beds at Dutch Gap. The question suggests itself whether at 
the close of the Jurassic an ice sheet did not cover the northern 
part of Scotland, extending east and west. If so, we may have 
in the melting of this ice, the source of supply of those waters 
which formed the fresh water Wealden deposits of England 
and northwestern Germany. It is well known that it is a pu2- 
zle to determine whence the great rivers which fed these lakes 
could have derived their abundant waters. 
Another question may be asked. Is it not possible that 
some of the drift of our northern States, which is attributed 
entirely to the action of forces in the Glacial Period, may be 
the attention of geologists. Sir Charles Lyell, in his account 
of his second journey to the United States, mentions some 
oe 
