Geologic Map and Digital Database of the Cougar Buttes 7.5' Quadrangle, San Bernardino County, California

The data set for the Cougar Buttes quadrangle has been prepared by the
Southern California Areal Mapping Project (SCAMP), a cooperative project
sponsored jointly by the U.S. Geological Survey and the California Division of
Mines and Geology, as part of an ongoing effort to utilize a Geographical
Information System (GIS) format to create a regional digital geologic database
for southern California. This regional database is being developed as a
contribution to the National Geologic Map Data Base of the National Cooperative
Geologic Mapping Program of the USGS. Development of the data set for the
Cougar Buttes quadrangle has also been supported by the Mojave Water Agency and
U.S. Forest Service, San Bernardino National Forest.

The digital geologic map database for the Cougar Buttes quadrangle has been
created as a general-purpose data set that is applicable to other land-related
investigations in the earth and biological sciences. In cooperation with the
Water Resources Division of the U.S. Geological Survey, we have used our
mapping in the Cougar Buttes and adjoining quadrangles together with well log
data to develop a hydrogeologic framework for the basin. In an effort to
understand surficial processes and to provide a base suitable for ecosystem
assessment, we have differentiated surficial veneers on piedmont and pediment
surfaces and distinguished the various substrates found beneath these veneers.
Currently, the geologic database for the Cougar Buttes quadrangle is being
applied in groundwater investigations in the Lucerne Valley basin (USGS, Water
Resources Division), in biological species studies of the Cushenbury Canyon
area (U.S. Forest Service, San Bernardino National Forest), and in the study of
soils on various Quaternary landscape surfaces on the north piedmont of the San
Bernardino Mountains (University of New Mexico). The Cougar Buttes database is
not suitable for site-specific geologic evaluations at scales greater than
1:24,000 (1 in = 2,000 ft).

This data set maps and describes the geology of the Cougar Buttes 7.5'
quadrangle, San Bernardino County, California. Created using Environmental
Systems Research Institute's ARC/INFO software, the data base consists of the
following items: (1) a map coverage showing geologic contacts and units, (2) a
separate coverage layer showing structural data, (3) a scanned topographic base
at a scale of 1:24,000, and (4) attribute tables for geologic units (polygons),
contacts (arcs), and site-specific data (points). The data base is accompanied
by a readme file and this metadata file. In addition, the data set includes the
following graphic and text products: (1) A portable document file (.pdf)
containing a browse-graphic of the geologic map on a 1:24,000 topographic base.
The map is accompanied by a marginal explanation consisting of a Description of
Map Units (DMU), a Correlation of Map Units (CMU), and a key to point and line
symbols. (2) Separate .pdf files of the DMU and CMU, individually. (3) A
PostScript graphic plot-file containing the geologic map on a 1:24,000
topographic base accompanied by the marginal explanation. (4) A pamphlet that
summarizes the late Cenozoic geology of the Cougar Buttes quadrangle.

The geologic map data base contains original U.S. Geological Survey data
generated by detailed field observation and by interpretation of aerial
photographs, including low-altitude color and black-and-white photographs and
high-altitude infrared photographs. The map was created by transferring lines
from the aerial photographs to a 1:24,000 topographic base via a mylar
orthophoto-quadrangle or by using a PG-2 plotter. The map was then scribed,
scanned, and imported into ARC/INFO, where the database was built. Within the
database, geologic contacts are represented as lines (arcs), geologic units as
polygons, and site-specific data as points. Polygon, arc, and point attribute
tables (.pat, .aat, and .pat, respectively) uniquely identify each geologic
datum and link it to other tables (.rel) that provide more detailed geologic
information.