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58 GUIDEBOOK OF THE WESTERN UNITED STATES 
Texas in 1930 was upon an outcrop of the upper member of the Mount 
Selman. The medial sand member, known as the Queen City sand in 
northeastern Texas, contains clay deposits, some of which carry fossil 
leaves, and the series is, for the most part, nonmarine. This sand 
member is uniform in character, and in the Winter Garden region in 
southern Texas it is sufficiently thick and pure to carry water of a 
quantity and quality second only to that in the Carrizo sand. Post 
oak and blackjack oak are the characteristic trees growing on the 
heavier sands, but where a little clay is mixed with the sand the 
forest growth is varied, and in well-watered areas the underbrush is 
heavy. 
The lowest member of the Mount Selman formation along the 
Southern Pacific Railroad has been separated as the Reklaw. It con- 
sists of ferruginous sands and brownish and grayish 
Harwood. glauconitic micaceous clays of marine origin, possibly 
Elevation ges less than 100 feet thick. The railroad crosses the out- 
ew Orleans 08 miles, CTOp zone, about 1 mile wide, at the small village of 
Harwood. The soil and landscape sharply reflect the 
lithology of this member, the clay outcrop forming a low flat belt and 
a heavy soil which in wet weather makes very difficult roads, whereas 
the ferruginous, concretionary beds at the base give much more relief 
and better-drained though muchrougherroads. Thehilly character of 
this region is due to the capping of these resistant basal beds of the 
Reklaw upon the soft, readily eroded Carrizo sand. Both the basal 
ferruginous layers and the clays above carry fossils. The ferruginous 
beds contain impressions of Venericardia and Corbula, which in places 
are fairly common; the glauconitic clays carry locally, notably on the 
Colorado River near Bastrop, a well-preserved and varied coral and 
molluscan fauna. 
On the western edge of Harwood the shale at the base of the Mount 
Selman formation gives place abruptly to the Carrizo sand, one of the 
most characteristic of the Texas Tertiary formations. The airplane 
maps show this formation as a solid pale-gray ribbon picoted along 
the margins by the darker pattern of the Reklaw above and the Indio 
beneath. The sand is coarse and almost pure white, and consists of 
nearly pure quartz grains, loosely packed and readily weathered, blow- 
ing about the fields and resisting cultivation. The bright-colored 
indurated layers occurring at intervals in the sand and the local 
capping of the Reklaw ferruginous strata along the eastern edge of the 
outcrop break down into rugged, castellated shapes, contrasting 
_ sharply in color and relief with the soft, dazzling white sand. Rather 
scrubby oaks are the most conspicuous trees, and the few and difficult 
roads wind through long uninhabited stretches broken only here and 
there by a lumber or goat camp. In certain Carrizo areas where the 
