Record of Geology of Texas, ISSV-lS^e. 
211 
Penrose, R. A. F., Jr. 
Amer. Jour, of Science, III, Yol. XXXA^'III, pp. 468-473. 
Dec., 1889. 
334. 
A Prejiminar}!^ Report on the Geology of the Gulf Tertiary of 
Texas from Red River to the Rio Grande. 
First Ann. Rept. of the Geof. Surv. of Texas, 1889, pp. 3-101. 
Austin, 1890. 
Contents: Introduction. iDeseriptive Geology — (Geography and Topo- 
graphy. ISitrat'igraphy. Basal or Wills Point clays. The Timber belt 
or Sabine Piver beds. The Fayette beds. Post Tertiary deposits. Eco- 
nomic Geology — Iron Ores otf East Texas. 'Benches. Building stones. 
Clays. Glass isands. Lime. Marls. Lignites ; ;San Tomas coal mine ; Uses 
of lignite; Analyses of lignite. Mineral springs. Oils. Salt. 
“The name East Texas is generally applied to that part of the State lying 
east of the Brazos river. This area is bounded on the north by Indian 
Territory and Arkansas, on the east by Louisiana, on the south by the 
Gulf of Mexico, and on the west by the great prairie region of Central 
Texas. A large part of this area is a heavily timbered region, and marks 
the southwestern terminus of the great Atlantic timber belt, extending 
from the Arctic regions continuously along the coast of the Atlantic ocean 
and Gulf of Mexico, until it finally disappears in the mesquite and cactus 
prairies between the Colorado river and the Rio Grande. 
“The country consists largely of the iii-shore part of the bottom of the 
old Tertiary Sea, which once covered the whole 'Gulf coast. This area has 
been elevated into a- table-land one hundred to seven hundred feet above 
the present sea level, sloping gradually to the southeast, and emptying its 
waters in the same direction into the Gulf of Alexico. iSince its elevation 
it has undergone great erosion, and is still being denuded at a tremendous 
rate. The strata are all composed of sands and clays, and succumb very 
'• readily to the erioding action of the atmospheric agencies. The result is, 
that iall that is left of the once level surface of this table land are a few 
flat-topped hills and ridges, such as are seen in the northeastern counties. 
East -Texas, as thus defined, comprises a coast prairie region on the south, 
a great timber region in the center, and an interior prairie country in the 
north and northwest. The coast prairies reach inland along the Sabine 
about fifty miles, but .as we go west they spread farther and farther towards 
the .interior until, when we come to the Brazos, they reach up the river 
for over a hundred miles. Near the Gulf shore they are flat and low, 
rising twenty to thirty feet above • tide water, thickly covered with grass 
and cut by steep-sided channels of many rivers and creeks. The monotony 
of the scenery is broken only by the narrow strips of timber which follow 
the meandering courses of the streams down towards the Gulf of Mexico. 
As we go inland the country slowly rises, and though the prairies in their 
easterly part maintain their flat character, to the west they become more 
undulating and broken, and groves of mesquite, hackberry, cottonwood, 
and other trees are seen in many places. Finally, we come to the beauti- 
