|arrow, certain||Landslide arrow|
|contact, certain||Landslide contact|
|Qs||Beach sands (Holocene)|
|Qd||Dune sands (Holocene)|
|Qls||Landslide deposits (Pleistocene and Holocene)|
|Qod||Older dune sands (Pleistocene)|
|Qt||Terrace deposits (Pleistocene)|
|Qoc||Olema Creek Formation (Pleistocene)|
|Qmi||Millerton Formation (Pleistocene)|
|QTm||Merced Formation (upper Pliocene to Pleistocene)|
|Twg||Wilson Grove Formation (upper Miocene to lower Pliocene)|
|Tp||Purisima Formation (upper Miocene to lower Pliocene)|
|Tsc||Santa Cruz Mudstone (upper Miocene)|
|Tsm||Santa Margarita Sandstone (upper Miocene)|
|Tm||Monterey Formation (middle to upper Miocene)|
|Tl||Laird Sandstone (middle Miocene)|
|Tpr||Point Reyes Conglomerate of Galloway 1977 (lower Eocene)|
|Kg||Porphyritic granodiorite of Point Reyes (Upper Cretaceous)|
|Kgr||Granodiorite and granite of Inverness Ridge (Upper Cretaceous)|
|Kqd||Tonalite of Tomales Point (Upper Cretaceous)|
|KJf||Franciscan complex (Jurassic and Cretaceous)|
|contact, certain||Observed contact|
|contact, concealed||Concealed geologic contact whose position is inferred|
|contact, approx. located||Geologic contact whose position is not precisely known|
|contact, inferred||Geologic contact whose position is inferred|
|fault, certain||Observed fault|
|fault, concealed||Concealed fault whose position is inferred|
|fault, approx. located||Fault whose position is not precisely known|
|fault, inferred||Fault whose position is inferred|
|water boundary||Boundary of a body of water|
|map boundary||Boundary of mapped area|
|oilwell||location of oilwell|
|map boundary,||Boundary of mapped area|
|f.a., anticline, approx. located||Anticlinal fold axis whose position is not precisely known|
|f.a., anticline, concealed||Concealed anticlinal fold axis whose position is inferred|
|f.a., syncline, approx. located||Synclinal fold axis whose position is not precisely known|
|f.a., syncline, concealed||Concealed synclinal fold axis whose position is inferred|
|flat bedding||Orientation of bedding that is basically horizontal|
|horz bedding||Horizontal bedding orientation|
|Range of values|
|Range of values|
We are grateful to Don Lewis, former chief geologist of Chevron, for the release of well data and to Robert Fleisher also of Chevron for providing microfossil slides of Chevron Oil Company wells. We also are indebted to Kris McDougall for identifying and interpreting microfossils, to Martin Link for measuring and interpreting the sedimentology of the Kehoe Beach section, and to the late Clyde Wahrhaftig for enthusiastically supporting this work and for collaborating with us on two field trips in 1990 and 1991 to the Points Reyes area. LeeRoy Brock, former Chief Park Ranger of Point Reyes National Seashore, greatly facilitated our field work in 1978 and 1979.
Carolyn Randolph, Heather Schoonover, and Carl Wentworth developed this digital version of the geologic map, and Carolyn Randolph prepared the booklet announcing the release of this database in Open Files. Partial funding was provided to Clark by USGS NEHRP award number 1434-HQ-96-GR-02741.
This digital map database, compiled from previously published and unpublished data and new mapping by the authors, represents the general distribution of surficial deposits and rock units in Point Reyes and surrounding areas. Together with the accompanying text file (pr-geo.txt or pr-geo.ps), it provides current information on the stratigraphy and structural geology of the area covered.
Are there legal restrictions on access or use of the data?
This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
This database, identified as "Geology of Point Reyes National Seashore and Vicinity, California: A digital database," 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.
ARC/INFO export files Description of coverage pr-geol.e00 Depositional contacts, faults, and unit labels pr-strc.e00 Fold axes, strike and dip information pr-arrows.e00 Landslide arrows pr-oil.e00 Oil well locations pr-topo.e00 Topographic contours base map pr-drain.e00 Drainage base map pr-outln.e00 Outline of map boundaryin format ARCE (version 7.x) Size: 15