314 = E. W. Hilgard on the Quaternary of Mississippi. 
seems to represent an immense delta, whose apex is in the neigh- 
borhood of the junction of the Ohio and Mississippi. _ Its eastern 
outline descends along the ridge of Carboniferous rocks skirting 
Alabama, however, as in Mississippi, it is but thinly represented 
on the territory of the “ Rotten Limestone.” 
The extreme western outline of the delta is, doubtless, to be 
sought in Arkansas, skirting on the east the high lands of that 
state, at the great channel of the Mississippi, however, Was 
already impressed upon the surface at the time of the deposition 
of this formation, is rendered obvious by the existence in 1, pat 
allel to that channel, of a belt of pebbles and coarse shingle, 
which at present reaches but a short distance (ten to fifteen miles) 
inland from the “bluff” or edge of the great bottom. It was 
deflected westward by the Tertiary ridge of the “ Walnut Hills, 
abutting at Vicksburg upon the Mississippi, the latter having 
almost entirely cut away the pebble deposit; it reappears, how- 
ever, below Grand Gulf, and thence again has spread southeast: 
ward across the state, so as to reach, in Marion Co., Miss. te 
waters of Pearl river. P 
While the Mississippi river is thus the legitimate modern oe 
resentative of the great ancient current which was capable 0 
transporting such coarse material, no one channel now remains to 
represent the corresponding stream (or bayou, as it would now 
e termed) on the eastern edge of the delta, whose existence 1D 
times past is certified by a similar band of pebble deposits a 
crossed in several directions by the drainage of the country ¢ 
traverses. Unlike the loose beds of the western band, those © 
ombigby. 
Such being the general disposition of these deposits, we are 
led to inquire into the origin of the great inundation of water 
se devoid of organic life, by which they were forme. 
hat traces of its existence has it left north of the latitude of 
the Ohio, whence the rush of waters evidently came 
northern geologist may pertinently retort: “ What became of 
that rush of waters whereof our Dri : evidence; 
after it left our latitudes ?” rift furnishes the 
