No positional accuracy information was prescribed to geologic contacts in the original report (such as approximate, concealed, etc), and thus all geologic contacts were attributed as well placed (certain, or solid lines) although the original nature of the contact is unknown.
No positional accuracy information was prescribed to geologic contacts in the original report (such as approximate, concealed, etc), and thus all geologic contacts were attributed as well placed (certain, or solid lines) although the original nature of the contact is unknown.
Map units (polygons) are described in the polygon attribute table (marlm-geo.pat). The identities of the map units are recorded in the PTYPE field by map label (i.e. Ts). For a description of the map units, consult the PostScript or PDF explanation pamphlets in this report.
Geologic lines (arcs) are recorded as strings of vectors and are described in the arc attribute table (marlm-geo.aat). They define the boundaries of the map units, the faults, and the map boundaries. These distinctions, including the geologic identities of the unit boundaries, are recorded in the LTYPE field. Attributes for geologic lines generally follow a scheme of the type of geologic line (i.e. fault), followed by a locational and/or scientific modifier (i.e. approx. located or queried).
This database, identified as "Digital Version of 'Open-File Report 92-182: Geologic Map of the Marl Mountains Quadrangle, San Bernardino County, California'" has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use.
Marl Mountains, California Database c/o Database Coordinator U.S. Geological Survey 345 Middlefield Road, M/S 975 Menlo Park, CA 94025
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The compressed tar file will be returned on the tape or CD-ROM. The acceptable tape type is: 2.3 or 5.0 GB, 8 mm Exabyte tape.