56 GUIDEBOOK OF THE WESTERN UNITED STATES 
topographically, for it is on the notably flat divide between the 
Colorado River, which heads far west in the outcrop area of the 
Permian ‘‘Red Beds,” and the Guadalupe River, which heads on 
the Edwards Plateau. The town site is just beyond the heads of the 
fingering tributaries of the intermediate coastal streams, such as the 
Navidad River. Obar Hill, less than a mile south of Flatents and 
rising more than 100 feet. aleve the village, is capped by heavy beds 
of white sandstone, probably an Oakville inlier. The well at Flatonia, 
3,000 feet deep, is supposed to obtain its excellent water supply from 
the Carrizo sand. 
The Fayette-Catahoula contact is about 1 mile west of the crossing 
of the old San Antonio & Aransas Pass Railway (now Texas & New 
Orleans) in Flatonia, where the fine-bedded sands of the upper Fayette 
lie below the greenish-gray compact clays of the basal Catahoula.*’ 
The varied lithology of the Fayette sandstone is expressed in the diver- 
sity of the landscape and the vegetation. The soil is more highly 
colored, as a rule, than that of the Catahoula, and the contrast 
between the black clay roads and post oak of the lower Catahoula and 
the red sandy roads and junipers of the upper Fayette is very striking. 
The configuration of the Fayette outcrop is noticeably different from 
that of the outcrop of the underlying Yegua formation, though it 
is not so rugged as that of the Catahoula and Oakville sandstones. 
A little more than a mile beyond Janice siding the railroad passes 
from the dominantly sandy Fayette strata to the Yegua beds, 
which are gray, green, and brown lignitic clays and sandy clays with 
thin sand deposits. They are highly gypsiferous and, for the most 
age nonmarine. They are about 500 feet thick, and all the beds dip 
to the east at a low rate. The outcrop zone is a region of low hills 
withgentleslopes. Generally the soil is dark and loamy with scattered 
mesquite (Prosopis julifiora) and prickly pear (mostly Opuntia engel- 
manni); more rarely itis a fine sandy loam with a few post oaks. The 
mesquites growing on Yegua soil in this region are larger than those 
in the region to the south, probably because of a greater supply of 
moisture. However, this plant withstands dry weather by sending 
its taproot as deep as 50 feet to obtain moisture. The mesquite, 
which begins to be conspicuous in this general region, is a dominant 
37 There are fine exposures of the for- 
mations in road and stream cuts both 
north of the railroad, toward Muldoon, 
and to the south, especially in the 
vicinity of Nickel, where 75 feet or 
more of kaolinitie shales and econcre- 
_ tionary sands and mes at the 
_ top of the Fayette are vada by the 
_ sandy clays filled with clay balls that 
characterize the | Catahoula, The 
Fayette formation consists of light-gray 
i ed sands, dark-gray and choc- 
olate-brown clays and lignites, and, in 
its upper part, thin beds of volcanic 
. The thickness is about 65 feet. 
The basal Fayette in this general section 
commonly carries cylindrieal concre- 
tions of iron oxide an inch or so in diam- 
eter oriented at a high angle to the 
bedding planes, 
