20 OIL FIELDS OF TEXAS-LOUISIANA COASTAL PLAIN, [bull. 212. 
2. Pleistocene, with probably some Pliocene. T /n C fel\ eSS 
a. Beaumont clays: Brown, blue, and yellow clays, carrying nodules 
of limestone in places irregularly distributed through the 
clays, making the soil black where found; brown and blue 
sands with great quantities of cypress wood and recent shells 25 to 400 
b. Columbia sands: White, yellow, gray, and mottled sands with 
beds of blue and yellow clay, some decayed wood, and a heavy 
deposit of gravel at base. In the clays belonging to these beds 
at Sour Lake such vertebrates as Mam in at, Megalonyx, Equ us, 
Smilodon fatalis, etc. , have been found « 50 to 200 
3. Neocene (Miocene, with probably some Pliocene). 
a. Lafayette sands: Blue and red thinly laminated clays; massive 
red and brown clays: and red and brown cross-bedded sands 
and gravels carrying pinkish inclusions of clay 30 to 375 
b. Blue, brown, and gray clays; sands with thin beds of limestone 
and c< mtaining small quantities of oil 300 to 4S() 
c. Blue clays and thin-bedded irregularly deposited sandstones 200 
d. Blue, red, and gray clays and sands and thin-bedded limestones; 
limestones dolomitized and associated with sulphur, gypsum, 
gas, and petroleum. Sands carry fossils of Miocene age 300 
4. Eocene. 
a. Frio clays: Blue, brown, red. yellow, and green clays, thinly 
laminated, partially stratified and massive. The laminated 
clays carry small crystals of gypsum and the massive clays 
numerous concretions of lime from 2 to 4 inches in diameter 
and calcareous-ferruginous concretions from 6 inches to 2 or 
more feet in length. Fossiliferous in places and changing to 
sandy calcareous clays to the west 200 
b. Fayette sands: Gray sands and gray and white sandstones inter- 
stratified with gray, white, and pink clays and sandy clays. 
The lower sandstones are often hard and glassy, and bluish 
or pinkish in color. The upper sandstones are soft and chalky 
white, and contain numerous casts of grass, reeds, palmetto, 
and other marsh plants. At some localities a thin bed of 
limestone in these upper sandstones carries Lower Claiborne 
fossils, and a yellowish-brown sand contains a considerable 
number of plant impressions 400 
c. Yegua clays: Dark-blue gypseous clays and dark bluish-gray 
sands with considerable deposits of lignite 1 , 000 
d. Upper marine beds or Cooks Mountain beds: A series of green- 
sands, fossiliferous greensands, fossiliferous clays, stratified 
black and gray sandy clays, black and yellow clays with limy 
concretions. A very prolific Claiborne fauna 390 
e. Mount Selman beds: Brown sands, blue clays, greensands, 
glauconitic sandstone, and heavy deposits of limonite. More 
or less fossiliferous, but fauna mostly represented by casts.. _ 260 
f. Lignitic: White, yellow, gray-brown, red, blue, and black sands 
with interstratified and interlaminated blue, gray, and brown 
clays with heavy beds of lignite. Apparently unfossiliferous 
except for a few plant remains, including the palmetto 1060 
g. Wills Point clays: Yellowish-brown sands containing bowlders 
of sandstone and limestone with some calcite concretions; 
dark-blue and brown laminated and massive clays and fossilif- 
erous white limestone 260 
5. Cretaceous. 
aLeidy, Extinct Vertebrate Fauna, vol. 1, Hayden Survey of Territories. 
