EL. W. Hilgard—Geological Reconnoissance of Louisiana. 848 
limestone of precisely similar character, near Chicotville in St. 
Landry parish, La., on the territory of the Grand Gulf group, 
which in the absence of other evidence, I had previously re- 
ferred to the latter (see above). Its absolute lithological iden- 
tity with the limestones of Northern Louisiana, as well as the 
incongruity with all other materials heretofore observed in the 
Grand Gulf or other Tertiary deposits, leave little room for 
doubt that here, within 70 miles of the Gulf coast, we have 
another Cretaceous summit rising out of the Tertiary. Andi 
we follow still farther the general line of trend, southeastward, 
we light upon the group of Five Islands, and notably the rock- 
salt deposit of Petite Anse. 
1t is perhaps too early to discuss the question, whether the 
latter coincidence is accidental, or whether this ancient Oreta- 
ceous ridge thus forming the “ backbone” of Louisiana, has 
caused, not only the shallowing of the older Eocene sea into 
marshes and lagoons, but also the eastward deflection of the 
lower Mississippi, and explains the simultaneous existence of 
salt both in North and South Louisiana, If rock-salt, however, 
should be found to form any part of the Cretaceous rocks of the 
southwest, a Cretaceous outlier at Petite Anse would be scarce- 
ly more strange than the limestone outcrop near Chicotville. 
he presumption is still farther strengthened by the phenom- 
ena observed in the wells bored near the West Fork of Calcasieu 
Tiver, about twelve miles west of Lake Charles in Calcasieu 
8 
The Artesian wells of Calcasieu.—These are located on two 
small islands in the (fresh-water) marsh which forms the he 
of bayou Choupique, a small tributary of the main Calcasieu 
river. It was long known that on one of these islands there 
existed “tar springs” which had formed an asphaltum pave- 
ment on a portion of the surface, and continually evolved com- 
bustible gas ; and not long after the close of the war, boring 
Operations were commenced there by the “ Louisiana Petroleum 
and Coal Oil Co.,” whose auger had, at the time of my visit, 
reached a depth of 1,230 feet. . 
Another bore has been commenced on an island about 700 
yards to the westward ; the work, now carried on by Dr. Kirk- 
man of Lake Charles, has reached a depth of 450 feet. The 
following is a comparative profile of both wells, sr 
The data for the following profile are derived, for position 
and thickness, from the statements of the well-borers ; the ma- 
terials are given from samples of the borings picked from the 
pile by them in my presence, and I have every reason to think 
that the facts are faithfully represented. 
As regards the interpretation of the formations penetrated, 
