These documents are useful references that are either out of print, difficult to obtain, unpublished, or the ink is so wet that they could only be published online.

Allen, V.T., 1929, The Ione Formation of California: Bulletin of the Department of Geological Sciences, University of California Press, Berkeley, California, v. 18, no. 14, p. 347–448.      view here

Christensen, Odin D., Christopher D.Henry, and Jim Wood, 2015, Origin of gold in placer deposits of the Sierra Nevada Foothills, California, Geological Society of Nevada Symposium 2015.     view here

Christensen, Odin, 2014, Gold Nuggets—Evidence of Past Climates and Former Landscapes, slide presentation given to the Geological Society of Nevada, February 21, 2014.          view here

Garside, Larry J., Christopher D. Henry, James E. Faulds, and Nicholas H. Hinz, 2005, The Upper Reaches of the Sierra Nevada Auriferous Gold Channels, California and Nevada,    view here

MacGinitie, Harry D., 1941, A Middle Eocene Flora From the Central Sierra Nevada; Carnegie Institution of Washington Publication 534, Washington, D.C.    view here

Pask, Joseph A. and Mort D. Turner, 1952, Geology and Ceramic Properties of the Ione Formation, Buena Vista Area, Amador County, California; Special Report 19, Division of Mines, California Dept. of Natural Resources, San Francisco.  view here

Schorn, Howard E., 2012, A Historical Review Of The Age Assignments Applied To The Chalk Bluff Fossil Plant Assemblage, Central Sierra Nevada, California;  unpublished.     view here

Wood, James L., J Reed Glasmann, and Scott Stout, 1995, Geology of the Ione Formation in the Ione Area,  1995 AEG Field Trip Guidebook: Geology and Geotechnical Aspects of the Ione Formation.    view here

Wood, James L., 1994, A Re-evaluation of the Origin of Kaolinite in the Ione Formation (Eocene), Sierra Foothills, California; MS Thesis document, California State University, Los Angeles.    view here

Yeend, Warren E., 1974, Gold-Bearing Gravels of the Ancestral Yuba River, Sierra Nevada, California; Professional Paper 772, USGS, Washington, D.C.    view here

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