a 
Geology and Mineralogy. 169 
the less, are in the same deposit with small gravel stones of 
northern origin: and pleces of northern limestone. The drift 
changes gradually into a true less, the product of aqueous agen- 
st known, 
so in the history of the drift, where the effects change gradually, 
are the records of “lost” epochs, and these “beds of transition” 
other. 
less was cotemporary with that of the bowlder clay in the Coteau 
de Prairie. There must be some explanation given for the coéx- 
d . 
clal epoch, intervened, the loam itself passing horizontally into 
the glacial deposits of that epoch. 
wm . R 
