Introduction:   This section provides an annotated reference list and links to reports and maps that describe the geology of the Sacramento area.**      References: Piper, A.M., Gale, H.S., and Thomas, H.E., 1939, Geology and Ground-Water Hydrology of the Mokelumne Area, California: U.S. Geological Survey Water-Supply Paper 780, 230 pp. with 10 plates (maps and hydrographs of the Mokelumne River). Piper et al, 1939 map   Piper et al, 1939 report   Notes about Piper et al., 1939: This paper is the first to name and define several local units, including the Valley Springs, Mehrten, Laguna, Arroyo Seco and Victor Formations.  It lists the type localities, and provides reference sections and descriptions.  This is a "must read" for the local units, but lithologic descriptions are not all accurate.  The Laguna Formation is described as having a granitic source, but a recent revisit to the type section revealed heavy volcanic input.  The map is excellent, and extends from the Cosumnes River in the north to Lodi in the South.  Older names are used (defined) here, including the Victor Formation. Olmstead, F.H., and Davis, G.H., 1961, Geologic Features and Ground-water Storage Capacity of the Sacramento Valley California: U.S. Geological Survey Water Supply Paper 1497, Washington, 249 pp. with 5 plates (maps and cross section). Olmstead and Davis, 1961 map   Olmstead and Davis, 1961 report   Notes about Olmstead and Davis, 1961: This paper and the attached map give a broad description of geologic units from the Sutter Buttes in the north to Lodi in the South.  Units described in this report and exposed in the Sacramento area include the Ione, Laguna and Victor formations.  Other units are also described from other parts of the Central Valley.  The map is accurate, but because of the large scale tends to lump units together.  Older names may be used for some units (i.e. the Victor Formation), and Pleistocene/Quaternary units (mostly gravels) are not differentiated. Shlemon, R. J., 1967a, Landform-soil Relationships in Northern Sacramento County, California:  Ph.D. dissertation, U.C. Berkeley, Department of Geography, 295 p. plus map and cross sections. Shlemon, 1967a map   Shlemon, 1967a dissertation   Notes about Shlemon, 1967a:  This dissertation describes the Ione, Valley Springs, Mehrten, Laguna, Arroyo Seco, Fair Oaks, Riverbank and Modesto Formations.  This dissertation and related AEG field trip guides are the primary source for information about the Fair Oaks unit, which was never formally described in the geologic literature.  The map that is included with the dissertation provides some of the most detailed mapping of Cenozoic units to the east and south of Sacramento.  It includes a good correlation chart and time scale for local units.   Shlemon, R.J., 1967b, Quaternary Geology of the Northern Sacramento County, California: Annual Field Trip Guidebook of the Geological Society of Sacramento, May 1967, 60 p. Notes about Shlemon, 1967b:  This is "Shlemon lite", the abridged version of the dissertation (above).  This guide contains a road log and guide that describe exact locations of outcrops for several local units.  Contains a good correlation chart and descriptions of units.   Shlemon, 1967b field guide   Shlemon, R.J., 1971, The Quaternary Deltaic and Channel System in the Central Great Valley, California: Annals of the Association of American Geographers, v. 61, p. 427-440. Shlemon, 1971 Notes about Shlemon, 1971:  This article provides information about the Mokelumne river fan system.  It is analogous to the Sacramento fan, with buried river channels overlying and incised into delta peat. Ford, R.S., 1972, Groundwater Geology of Northern Sacramento County: University of the Pacific Spring Conference- Far Western Section, National Association of Geology Teachers (NAGT), April 23, 1972, 23 p.  Includes a road log with exact distances between outcrops. Notes about Ford, 1972:  Contains a good road log, and correlation chart for local units.  Descriptions are limited, but it will help locate units in the field. DWR Bulletin 118-3, 1974, Evaluation of Groundwater Resources, Sacramento County: Department of Water Resources, Sacramento, 139 p., with map. DWR Bulletin #118-3 map   DWR Bulletin #118-3 report   Notes about DWR Bulletin 118-3: This report, cross sections and map provide the best summary of local geology and stratigraphy.  Units are correlated in the subsurface using cross sections, and the map is a good composite of commonly used geologic names.  This is the standard reference for many reports, and should be the starting point for questions about local stratigraphy.   Huntington, G.L., Begg, E.L., Harden, J.W., and Marchand, D.E., 1977, Soil Development, Geomorphology, and Cenozoic History of the Northeastern San Joaquin Valley and Adjacent Areas, California:  A guidebook for the joint field session of the American Society of Agronomy, Soil Science Society of American and the Geological Society of American:  344 p. Huntington, Begg, Harden and Marchand, 1977 Notes about Huntington et al., 1977:  This publication focuses on soil description but has information about the Turlock Lake Formation, China Hat Formation, Ione Formation and other units. These names are often used North of Sacramento.  The Riverbank Formation is described in detail, and the Laguna, Mehrten and Valley Springs Formations are mentioned.   Helley, E.J., and Harwood, D.S., 1985, Geologic Map of the Late Cenozoic Deposits of the Sacramento Valley and Northern Sierran Foothills, California: USGS Miscellaneous Field Studies Map MF-1790, 24 p. with 5 plates (maps) in pocket. Helley and Harwood, 1985 map sheet 1 Helley and Harwood, 1985 map sheet 2 Helley and Harwood, 1985 map sheet 3 Helley and Harwood, 1985 map sheet 4 Helley and Harwood, 1985 map sheet 5   Helley and Harwood, 1985 Summary report   Notes about Helley and Harwood, 1985:  This is the most recent attempt at re-mapping the Central Valley.   Five sheets extend from south Sacramento (Sheet 1) almost to Shasta Dam in the north (Sheet 5).  These maps use common unit or formation names, and are a standard reference for local stratigraphy and unit names.  Mapping is limited to the Central Valley and a narrow edge of the Sierran foothills.  The report is very brief, so descriptions are limited and the main value is the map set. Glasmann, R.R., Wood, J., Bieber, D., Jenkins, D., McDonnell, M., and Stout, S., 1995, Geology and Geotechnical aspects of the Ione Formation:  Association of Engineering Geologists Field Trip Guide, 1995 Annual meeting, October 3-8, 1995, Sacramento CA. Notes about Glasmann et al., 1995: Focuses on the clay mineralogy and industrial applications of Ione clays. Shlemon, R.J., 1998, Quaternary Geology of the Sacramento Area: Association of Engineering Geologists, Sacramento Section Field Trip Guidebook, March 21, 1998, 21 p. with references as attachments. Notes about Shlemon, 1998:  This is a revision of a field trip that Roy Shlemon ran in 1967.  Contains several newer articles as attachments.  Includes a good correlation chart and time scale for local units. Shlemon, R.J., Horner, T.C., and Florsheim, J., 2000, Quaternary Geology of the Sacramento Area: Association of Engineering Geologists, Sacramento Section Field Trip Guidebook, March 25, 2000, 38 p. with references as attachments. Shlemon et al, 2000 field guide   Notes about Shlemon et al., 2000:  This is a recent re-hash of the 1998 field trip led by Roy Shlemon.  Stops are slightly different than the previous trip, but most figures and references are identical.  New sections by Florsheim and Horner explore different interpretations of depositional environments.  Includes a good correlation chart and time scale for local units. Creely, S., and Force, E.R., 2007, Type region of the Ione Formation (Eocene) Central California: Stratigraphy, Paleogeography, and relation to Auriferous gravels:   USGS Open File Report 2006-1378, 65 p. Notes about Creely and Force, 2007:  This paper provides a recent re-interpretation of the depositional environments of the Ione Formation. Springhorn, S. T., 2005:  Stratigraphic analysis and hydrogeologic characterization of Cenozoic strata in the Sacramento Valley near the Sutter Buttes.  M.S. Thesis, CSU Sacramento, 246 p. Springhorn, 2005 thesis   Notes about Springhorn, 2005:  This thesis is a very complete summary of Tertiary and Quarternary stratigraphy in the northern Central Valley.  It includes correlation charts that compare names used by different authors, and provides new information about stratigraphy near Sutter Buttes. **Annotations are the opinions of Tim Horner, CSUS Geology Department.  Copies of older, out of print maps are made available as a service to the public, and are not intended to bypass copyright laws or rights of owners.