86 E. W. Hiigard—Geology of Lower Louisiana. 
ishes of Sabine and Natchitoches, Koch limestone and sand- f 
stone ridges also exist, is a question open. In the latter 7 
case, this outline would conform to the general shore lines of | 
the great cretaceous and tertiary Mediterran . | 
In Mississippi, the Grand Gulf series is poaily overlaid AM - 
the Orange Sand, deposited on a deeply eroded surface, and fF 
bearing itself the ‘evidence of its formation by fresh water in . 3 
state of violent flow.* The southern outline of the main body — 
a broad band of shingle extends toward Harrisonburg, Cata- | 
houla parish. This belt pea, probably, the most west- 7 
erly bayou of the great Orange Sand Delta; while, as hereto- fF 
fore stated, the most easterly one extends from the neighbor- — 
hood of Cairo along the western shore of the senna river, — 
down the valley of the Warrior toward the coast of ama. § 
The middle and main pebble-stream evidently fltses 4 in gen- f 
eral the course of the Mississippi river ; but leaving it at the 7 
point where that river suffers its remarkable deflection east- | 
ward, we find the remnants of its ancient “bar” in the chain 
“is evident ¢ 
the r 
‘period of 
rary diminution of the 
waters, through the cessation of subsidence, panne 
D this of quiet might have e begun the formation 
of those extensive swamp and lagoon deposits, the lower mem- 
* Am, Jour. Science, May, 1866; ne Senet we £. 
caused by a tempo: 
