by Warren Yeend – A rare USGS Professional Paper 772 that was hard to find until now. The paper covers the unmined tertiary placer deposits of the Ancestral Yuba River deposits. Many of these were mined by Hydraulic methods but there are still lots of areas, some which this book covers. Other areas are still yet to be found as these gravels spanned a large area that was then moved by mountain building processes, erosion faulting and the like. Lots of Maps showing Gold bearing areas, maps of mines, pictures and more. Now back in print by Sylvanite Publishing.