Geologic Map of the Maysville Quadrangle, Chaffee County, Colorado

granted us access to their land for mapping purposes. Of special note is Mrs. Norma
Friend, owner of the ranch at the mouth of Little Cochetopa Creek.
We thank Terry Klein and Ed DeWitt from the U. S. Geological Survey for peer
reviews of the manuscript and Jane Ciener for the technical review. Matt Morgan with
the Colorado Geological Survey was of great assistance during the ERDAS digitizing of
the preliminary geologic contacts. We thank Larry Scott with the Colorado Geological
Survey for preparation of report digital figures. We also thank Digital Data Services and
especially Tom Neer for preparation of the final digital geology map (plate 1),
Correlation of Map Units (plate 2), and geologic cross sections (plate 3).
DESCRIPTION OF MAP UNITS
SURFICIAL DEPOSITS
Quaternary (surficial) deposits cover the largest surface area of the Maysville
quadrangle. The combined Quaternary deposits are estimated to cover about 40 percent
of the area, mostly in the central, west-central and east-central parts of the map area.
Quaternary deposits shown on the map are generally more than 5 ft thick.
HUMAN-MADE DEPOSITS
af Artificial fill (latest Holocene) – Unsorted silt, sand, and rock fragments
deposited during human construction. Mapped only at the dam impounding Fooses Lake.
The average thickness of the unit is less than 30 ft. Artificial fill may be subject to
settlement when loaded if not adequately compacted.
GLACIAL DEPOSITS – Gravel, sand, silt, and clay deposited by ice along glaciated
valleys in the Sawatch Range (from north to south, Squaw Creek, North Fork South
Arkansas River, South Arkansas River).
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