Miscellaneous ied Topics, &c. 49 
iw: X.—Miscellaneous: Gooteirieil Topics relating to the dete 
part of the vale of the Mississippi; alluvion by rain; up — 
and extension of valleys; subsidence of the sea; original vale of 
the river with its wings and present channel.—From u: ishet 
MSS. on the Theory of the Earth; by Dr. Rusu Nort, of 
Rodney, Mississippi. 
_Tuar the ocean once rolled its waves over the present Delta of 
the Mississippi does not admit of a doubt. We will first consider the 
tract of country, from Vicksburgh to Baton Rouge, whose width is 
between ten and fifteen miles from the present boundary of the bluff. 
SKETCH OF THE COUNTRY. 
The unevenness of the face of this district will at once strike the 
traveller with surprise. It is a country cut to pieces by broad ravines; 
and notwithstanding the narrowness of the ridges, they are much dis- 
figured by excavations, running into their sides. The general eS 
tion of the principal ridges is westerly, intersecting the Mis 
right angles, and they are gradually depressed, as they run from o 
limits of the district now under consideration, until they are cut off | by 
the vale. | 
Most of the bluffs are from one to two hundred feet in height. By 
observing their descent, which is often gradual, when receding from 
the bluff to the limit of the territory we are now describing, it would 
appear that, did the ridges run upon a declivity similar to that which 
they formerly had, they would extend at least ten or fifteen miles 
farther than they now do, in a similar course. We shall then sup- 
pose, that prior to the existence of the present river, these blufis were 
i and terminated by a gentle declivity ; being met by a slight 
subsidence on the other side, which was an extensive ravine, that 
was afterwards to become the present vale; thus they gradually en- 
roached upon the basin, and finally succeeded in driving out the 
waters of the gulf, which we shall consider as the Natches basin. 
COMPOSITION OF THE STRATA. 
In proof of the correctness of our position, we shall appeal to the 
fact, of the presence of molluscous testacea, which are found to be 
very regularly and generally dispersed from within five feet of the 
present surface down to the sand, which formed the downs and beach 
of the ocean itself. The first foot of soil we shall - vegetable 
Vou. XXUI.—No. 1. 7 
lhe BUT, GARDE). 
1911 
