Record of Geology of Texas, ISSY-lSOe. 
77 
Drake, F. F. 
extend six or seven miles from the hase of the escarpment and nearly 
, surround the plains hy a narrow band, as is shown on the map. * * * 
‘Ws is there shown, this belt extends through latan, Mitchell county; 
'Grail, Borden county; 'Boekum and lEspuela, Dickens county; Goodnight, 
lArmstrong coimty; three miles north of Amarillo, Potter county; center 
of Oldham county; Liberty, New Mexico, and, with some breaks, down 
the east side of the Pecos river to Castle Mountains, 'Crane county. The 
formation spreads out to a considerable width in the vicinity of Liberty, 
'ISew Mexico, and west of the Pecos river opposite Fort 'Sumner. 
“The nearly horizontal strata of sandstone, conglomerate and clay, vary- 
ing in thickness and lesistance to erosion, have been carved into by 
branches, ravines and creeks, leaving a rolling landscape. The regular 
undulating nature of the beds is occasionally interrupted by more or less 
precipitous outcrops of sandstone or conglomerate strata. These rocks, 
resisting erosion longer than the others, often remain capping some point 
or ridge, walling in the narrow valley of some creek, or forming the channel 
wall of some ravine or branch. These sandstones or conglomerates are, 
however, rather soft, and their outcrops are not usually conspicuous away 
from the rapidly carving action of the streams, but give a rolling character 
to the surface by slightly holding in check the wear of points here and 
there, while the intervening softer rocks are worn deeper and deeper. 
“The topography of the Triassic beds is undoubtedly affected to some 
extent by irregularities in the erosion of the overlying Tertiary beds. This 
erosion, first marking the places that are afterwards worn down into 
drainage courses or left as dividing ridges. 
“Going back from the foot of the Plains to where the Dockum beds 
disappear, the rolling nature of the country grows somewhat less, and in 
some places is quite level. 
“Sandstones, conglomerates, and clays constitute nearly all the strata 
of this formation. 
“The materials composing the different strata vary somewhat in litholog- 
ical characteristics at different localities, and even at the same locality, 
but the general characteristics are quite uniform,, and are so different 
from the underlying Permian and overlying Cretaceous or Tertiary, that 
they are usually easily recognized. This is especially true of the sand- 
stones and conglomerates.’^ Pp. i 227 - 228 . 
110 . 
Report on the Colorado Coal Field of Texas. 
Fourth Ann. Rept. o'f the Geol. Snrv. of Texas, 1892, Pt. 1, 
pp. 355-446; 1 cut; 2 plates; 2 maps. Austin, 1893. 
Contents: Introduction: Hydrography; Topography; iRelations and 
Extent of tFormations ; Acknowledgments. General Geology: Cretaceous; 
Trinity Conglomerate, Trinity ISands, Alternating, Paluxy, and Texana 
Beds, Comanche Peak Limestone, Ca:prina Limestone. Carboniferous: 
Origin of the Sediment of the 'Strawn and Overlying Divisions; Strawn 
Division; Canyon Division; Cisco Division; lAlbany Division. Economic 
Geology: Coal; Chaffin iSeam, Upper or Bull Creek 'Seam, The Chaffin 
Coal, Bull Creek Coal iSeam. Oil and Gas; Origin of Oil and Condi- 
