30 MALONE JURASSIC FORMATION OF TEXAS. [bull.-26« 
underlying the Orbitolina limestone (Section IV of map). The suc-I 
cession from the Orbitolina limestone eastward down the mountain, 
is as follows : 
Feed 
1. Alternating thin beds of sandstone and clay, with occasional bands of 
limestone: Exogyra texana near the middle 201 
2. Alternations of limestone and covered spaces 200J 
3. Sandstone 8 
4. Covered 15 
5. Sandstone with Aetreonella dolium 15 
G. Argillaceous limestones, clays, and some arenaceous bands, with occa 
sional layers containing Exogyra texana 300J 
7. Limestone in several massive beds interstratified with more or less ar- 
gillaceous nodular beds: some of the harder bands full of Caprina 
occidentalis Conrad 75 
Farther oast some of these beds are repeated, dipping eastward. 
It is evident that these bods are in part the equivalent of those de-j 
scribed by Tat! as occurring in Flat Mesa, 4 miles north of Sierra 
Blanca, and that they should be included in the Fredericksburg 
division. 
About 10 miles south of Quitman Canyon and loss than 2 miles 
south of the northern boundary of the Eagle Mountain quadrangll 
the east face of the mountain shows a similar section, and at its base 
there are small exposures of Washita bods with Schlambachia ves\ 
pertina and a few other forms, dipping Coward the mountain and 
thus giving additional evidence of overturning and faulting. 
The Rio Grande section. — Still farther south, near the Rio Grande, 
the upper part of the section is much more complete and more simple, 
furnishing the key to the sections already discussed, which are par-] 
allel with it across the same line of uplift. The eastern end of the 
-eoi ion is about 1 mile north of the Rio Grande in the first hills west 
of the board valley of Quitman Arroyo. Here the beds are sharply 
folded and a prominent ridge shows an anticline consisting of argil 
laceous limestone belonging to the Washita division. 
The western limb of the anticline dips 70° to 80° west, and the ox 
posure is as follows : 
Rio 
section in hills just nest of Quit mini Arroyo, aoout I mile north of the 
Grande < section \ of map). 
I Vet. 
1. Argillaceous limestone, weathering in nodular form, with bands of 
harder limestone - 200 
12. More massive limestone, much seamed and Assured 30 
3. Dark, fissile shale, with occasional bunds of impure brown limestone. 
underlying a valley about 1 mile wide Dips at first steep to the 
west, becoming variable and much less toward the middle of the 
valley and again steep to the west on the west side of the valley. 
Inoeeramus labiatus and a few other Upper Cretaceous fossils were 
found wesl of the middle of the valley; thickness apparently sev- 
eral thousand feet. 
