Geologic map of the Cape Mendocino, Eureka, Garberville, & southwestern part of the Hayfork 30 X 60 Quadrangles and Adjacent Offshore Area, Northern California

This database and accompanying plot files depict the distribution of geologic
materials and structures at a regional (1:100,000) scale. The report is
intended to provide geologic information for the regional study of materials
properties, earthquake shaking, landslide potential, mineral hazards, seismic
velocity, and earthquake faults. In addition, the report contains new
information and interpretations about the regional geologic history and
framework. However, the regional scale of this report does not provide
sufficient detail for site development purposes. In addition, this map does
not take the place of fault-rupture hazard zones designated by the California
State Geologist (Hart and Bryant, 1997). Similarly, the database cannot be
used to identify or delineate landslides in the region.

This digital map database, compiled from previously published and unpublished
data, and new mapping by the authors, represents the general distribution of
bedrock and surficial deposits in the mapped area. Together with the
accompanying text file (ceghmf.ps, ceghmf.pdf, ceghmf.txt), it provides current
information on the geologic structure and stratigraphy of the area covered.
The database delineates map units that are identified by general age and
lithology following the stratigraphic nomenclature of the U.S. Geological
Survey. The scale of the source maps limits the spatial resolution (scale) of
the database to 1:100,000 or smaller.

This is the pre-release version of the report. The accompanying text file
mf2336.rev contains version numbers for each part of the data set.

This report consists of a set of geologic map database files (Arc/ Info
coverages) and supporting text and plotfiles. In addition, the report includes
two sets of plotfiles (PostScript and PDF format) that will generate map sheets
and pamphlets similar to a traditional USGS Miscellaneous Field Studies Report.
These files are described in the explanatory pamphlets (ceghdesc and ceghdb).
The base map layer used in the preparation of the geologic map plotfiles was
downloaded from the web (www.gisdatadepot.com) as Digital Raster Graphic files
of scale-stable versions of the USGS 1:100,000 topographic maps and coverted to
TIFF images which were then converted to GRIDs. These grids contain no
database information other than position, and are included for reference only.
The base maps used were the Cape Mendocino (1989 edition), Eureka (1987
edition), Garberville (1979 edition), Hayfork (1978 edition) 1:100,000
topographic maps, which all have a 50-meter contour interval. The bathymetry
maps were converted from the Coast and Geodetic Survey hydrographic chart 1308
N-12, 1969.