118 GUIDEBOOK OF THE WESTERN UNITED STATES 
From Small siding the railroad proceeds west down a small valley 
cut deeply in pink loams or sandy clays; these appear to have been 
deposited in a lake that once occupied the area, probably caused by 
the damming of the Rio Grande temporarily by some earth movement. 
About 1% miles beyond Small and at intervals to Finlay there are fine 
views of the Malone Mountains * showing sharply flexed limestones 
of Jurassic age. The most noticeable feature is a syncline or trough, 
which is clearly discernible from the train, as shown in Plate 17, B. 
Flexing and faulting have brought Permian gypsum to the surface 
along the railroad halfway between mileposts 756 and 757, where it is 
extensively quarried for use as plaster of paris. The quarry is 
south of the tracks. Near the quarry the gypsum is overlain by 200 
feet of conglomerate and light-brown conglomers tic sandstone, which 
is overlain by limestone interbedded with sandstone, the latter in part 
conglomeratic. Certain fossils at this horizon are believed by Baker 
to indicate Cretaceous age but earlier than any Trinity elsewhere in 
Texas. The gypsum is known to be of Permian age because an over- 
lying limestone, exposed half a mile east of Torcer siding, carries the 
characteristic fossil Richthofenia. Next above this are Jurassic beds. 
~ 
Horizontal scale 
' 
2 Miles 
Vertical scale 
o 4000 Feet 
Fieure 24.—Section across the Malone Mountains, Tex. After C. L. Baker (per- 
sonal communication). Jm, Malone limestone (Jurassic). Cp, Limestone, ete.; g, 
gypsum (both Permian) 
The gypsum also underlies the flat between the southeast end of 
the Malone Mountains and the intrusive mass of the Quitman Moun- 
tains. In the foothills of the Malone Mountains it is overlain by 
* According to Baker, the dominant 
structure in these mountains is 
axis passes near the gypsum quarry on 
the railroad. the southeast side 
a 
syncline overturned on its southwest- 
ern flank, a feature which is conspic- 
uous from afar along the summit of the 
of the syncline there is an overthrust 
to the northeast. There is much minor 
crumpling on the southeast end of the 
main northeastern ridge. The general 
features are shown in Figure 24. 
8 Clare i ae ra , 
; aoe, Ree 
with about 20 per cent of combined 
water. Plaster of paris, which is used 
extensively in the arts, is made from it 
of the combined water and grinding the 
resulting mass to fine powder. 
