28 OIL FIELDS OF TEXAS-LOUISIANA COASTAL PLAIN, [bull. 212. 
have any definite position among the clays. It is true that they 
always accompany the blue clays, but they are always found scattered 
in small pockets and occupying irregular patches a few acres in 
extent. It is possible that by some chemical action during or after 
the deposition of the clays the lime had been segregated into small 
depressions or softer portions of the clays. 
The country occupied by these clays is flat and, as a general thing, 
poorly drained. As a result the greater portion is unforested. Occa- 
sional mottes of small trees appear scattered over the prairie, and 
straggling lines of timber are found along the banks of the water 
courses. Owing to these conditions very Little knowledge of the 
structure can be obtained from the surface; nowhere do we find 
sections exposing more than a few feet, and these show only the pre- 
vailing bed of clay. Knowledge of the structure of this, area can 
be gained only from the records of the various wells. Along the 
Neches in the vicinity of Beaumonl and on Pine Island Bayou a few 
natural sections occur. At Beaumont the beds are seen to be lami- 
nated blue clays with brown partings, and on Pine Island a small sec- 
tion of blue and yellow clays is shown. 
This series of clays and sands has been named the Beaumont 
beds, from its greatest development in the neighborhood of that city, 
sections showing as much as 400 feet having been obtained from 
many of the wells. The greatest areal extent of these beds is found 
between the Trinitj^ and the Sabine rivers in Texas, where the maxi- 
mum width, north ami south, is a little over 20 miles. To the east 
of the Neches River their outcrops narrow rapidly, forming but a 
narrow strip across Orange County. In the Louisiana regions they 
appear to widen again to a considerable extent. These clays occur 
at Lake Charles and extend eastward in a broad belt to Abbeville, 
in Vermilion Parish. Passing westward from Beaumont, the areal 
extent of these clays decreases gradually to a few miles, and though 
they have been traced as far west as the Guadalupe River, in Cal- 
houn County, they do not appear to again widen greatly, though their 
chief characteristics remain constant. The Beaumont beds can usu- 
ally be detected by the peculiar nature of their soil, which is in many 
places highly calcareous, while the accompanjing clays are black, 
owing to the mixture of lime and the decaying vegetable matter 
contained in the clay. 
The well sections given on pages 132 and 136 show the relations of 
these clays to the underlying clays in the Louisiana parishes, and the 
records given of deep wells in the oil-producing areas show their con- 
nection in Texas. 
Large tracts where the Beaumont clay is exposed lie in very nearly 
the same marshy condition as the coastal marsh country itself. In 
some areas the surface blue and yellow clays form a low bluff or ridge, 
separating the two divisions. This is more noticeable in the Louisiana 
regions than in Texas. 
