THE CARRIZO SANDS. 
E. T. Dumble. 
The Carrizo sandstone was first described by Mr. J. Ow r en from 
the exposure around Carrizo Springs, Dimmit County, Texas. He 
gave the beds a thickness of 200 feet, the base being composed of 
gray and brown sandstone locally firm enough for building material 
and the upper part a red sandstone which gives a characteristic 
color to the soil. 
Mr. W. Kennedy found a series of sands in Cass County which he 
described as the Queen City beds from their exposure near that place. 
These comprise red and white sands, the red appearing as red 
blotches on the white, and have a thickness of 70 feet at this locality. 
No fossils were found. 
Further work demonstrated the fact that these two beds were part 
of a single deposit, and from their relations to the underlying beds 
in Cass County, they were considered to be the upper member of the 
Lignitic stage of the Eocene, and were so described. 
More recent examinations in Western Texas and Northeastern 
Mexico have brought out facts which disprove this reference and 
connect them more clearly with the Claiborne stage. 
In a recent study of the Rio Grande region, Mr. W. Kennedy 
finds that in this section, instead of being somewhat similar in com- 
position to the top of the Marine beds and lying in apparent con- 
formity with them, as in Eastern Texas, the Carrizo sands are here 
materially different from the underlying Lignitic, and that w T hile 
the Lignitic shows a rather strong dip for the Tertiary, the Carrizo 
sandstones lie at a very gentle inclination. Indeed, these sandstones 
not only die uncomfortably on the Lignitic, but overlap both it and 
the underlying Midway, and are found resting upon the Escondido 
or upper Cretaceous sediments in many places. 
A bluff on the Rio Grande between the Penitas and Caballero creeks 
shows the Midway at the base, with its characteristic fossils overlain 
unconformably by about 70 feet of the Lignitic, and this in turn is 
overlain unconformably by the Carrizo sandstones. 
A bluff a mile below the mouth of Penitas creek shows the Car- 
rizo sands resting unconformably directly upon the Midway without 
any appearance of Lignitic. 
There are numerous good exposures along Amole and Juanes 
creeks to the Ciga del Macha, a range of hills which extend south- 
ward some forty miles. In this region there are several points 
where the Carrizo sands rest directly upon the uppermost beds of 
