336 E. W. Milgard—Geological Reconnoissance of Louisiana. 
the deposits themselves, prove the action, especially at first, of 
violent currents, capable of transporting pebbles of several 
pounds weight, hundreds of miles from their original site.* 
follows (always provided that the ocean level remained sensibly 
constant) that the 900 feet change of level, at the mouths of 
the Mississippi, must have been accompanied by a considerably 
greater change near its head, one which would more than suf- 
fice, at the present time, to establish water communication be- 
tween the Gulf of Mexico on one hand, and the Gulf of St. 
wrence, as well as (through the ancient channel described, 
at the Chicago meeting of the Association, by Gen. G. K. 
Warren) with Hudson’s Bay and the Arctic basin on the other ; 
sufficiently great to explain the glaciation of the continent, as 
well as the succeeding fresh-water flood, whose effects are no 
less prominent in the southwestern portion of the North 
American continent, than those of the glaciers are in the north- 
ern. And it seems probable that the detailed study of this 
posits, over its wide area of occurrence 
prevent the formation of beach lines, or cause their remova! 
subsequent to deposition. If we assume the glacial epoch to 
have resulted chiefly or wholly from an uprising of the , 
(and perhaps of the sea-bottom also) in northern latitudes, the 
wide distribution of its effects there points to a universality 
and uniformity of cause, quite analogous to that which seems 
to obtain in reference to the southern or Stratified Drift, from 
these great events were not confined to the Atlantic slope ; # 
that the auriferous gravel beds of California are, in all proba- 
bility, the strict equivalents of the “Orange Sand” of Missis- 
sippi ; while the period of time required to cover the pebble 
* See Mississippi Rep., 1860, pp. 13, 26, et al. 
