This historic book may have numerous typos and missing text.
Purchasers can download a free scanned copy of the original book
(without typos) from the publisher. Not indexed. Not illustrated.
1912 Excerpt: ...the underlying formations over considerable areas.
The low and relatively recent flood-plains have been shown where
best developed bordering the larger water courses; of the next
older and higher deposits, the Leona formation, there have been
shown on the map the large areas lying southwest, south, and
southeast of San Antonio; of the highest plain, referred to the
Uvalde formation, there have been shown some areas in which the
formation occupies uninterruptedly several square miles. All of
these flood plains are more extensive than is here shown. Because
of the presence of these surface materials, the boundary between
the successive marine formations is necessarily placed in parts of
the county on data from limited exposures, supplemented by well
records. Where the surface is entirely obscured, the approximate
boundary of the underlying marine formations has in some instances
been indicated by broken lines, the data for placing the boundary
being obtained chiefly from well records. As information is
accumulated on the geology of this and the adjoining counties, the
boundary lines of the formations can be more exactly determined. In
mapping structure the Del Bio has been used as a key horizon and
the contours are drawn as on the top surface of this formation. In
using well records and reducing elevations to sea level it has been
necessary to determine the approximate surface level of the wells
from the topographic map. In that part of the county for which
there is no topographic map the elevations for wells near the
public roads have been obtained from the profiles of public roads
made by the County Engineer of Bexar County, kindly made accessible
for this purpose. In a few wells not on the area topographically
mapped and remote from the public roads, an es...
|Country of origin:
Elias Howard Sellards
||246 x 189 x 3mm (L x W x T)
||Paperback - Trade
Is the information for this product incomplete, wrong or inappropriate?
Let us know about it.
Does this product have an incorrect or missing image?
Send us a new image.
Is this product missing categories?
Add more categories.
Review This Product
No reviews yet - be the first to create one!