90 
TRANSACTIONS OF THE TEXAS ACADEMY OF SCIENCE. 
all instances. There is generally a depression surrounded by wooded 
hills in which are found limestones of white or gray color. The depres- 
sion is sometimes marshy, or during the winter months holds a body of 
water of greater or less extent, which evaporates as the summer ap- 
proaches and leaves an incrustation of salt on the ground. 
"The limestones are white to grey in color, and are sometimes quite sili- 
ceous, and sometimes they are glauconitic. They are characterized espe- 
cially by the seams of calcite they contain, and are proved by their fossil 
contents to he the equivalents of the Ripley group (Cretaceous) of Mis- 
sissippi. The underlying clays belong to the Ponderosa Marls, numbers 
of this oyster being found at different places in them. 
"Surrounding these salines on every side we find strata of Tertiary 
age, and the salines themselves are therefore in the nature of Cretaceous 
inliers in that formation. They represent islands in the Tertiary sea 
formed by projecting eminences of the underlying strata of Cretaceous 
age. 
"These salines occur also in Louisiana, where they have been studied 
by E. W. Hilgard and E. Y. Hopkins.* ‘The only known exposures of 
the limestones are. at Winfield and near Chicot, in St. Landry’s parish. 
The same strata, however, came very near the surface at all the various 
salt wells in Bienville and Winn parishes, and is the formation to which 
the sulphur of Calcasieu and the rock salt of Petit Anse belong.’ 
"Hilgard regards the series of Cretaceous inliers ‘which traverse Louis- 
iana from the head of Lake Bistenau in a south-southeast direction, 
terminating probably in the great rock salt mass of Petit Anse’ as repre- 
senting ‘summits of an (more or less interrupted) ancient ridge, a kind 
of backbone to the State of Louisiana, whose resistance to denudation 
has measurably influenced the nature and conformation of subsequent 
deposits.’! The connection between these salines and the strata con- 
taining them and the deposits of oil, sulphur, and gypsum existing in 
southwestern Louisiana is well worthy of notice. 
"At the sulphur mine in Calcasieu parish the boring of a well twelve 
hundred and thirty feet deep showed oil for the first three hundred and 
eighty-three feet. 
" ‘The evidence of oil consists of a number of black hanks of hardened 
bitumen on the northern border of the marsh prairie and on its surface; 
also quite a number of bubbling springs, emitting an inflammable gas; 
and crude petroleum may he found by walking over the marsh. So 
abundant is this natural discharge of crude oil that the log haulers for 
* First Annual Report Geological Survey of Louisiana, F. V. Hopkins, M. D., 
p. 206. 
fGeol. Hist, of the Gulf of Mexico, A. J. S., vol. 2, Dec., 1871, pp. 209, 210, 
