File:Annual report of the State Mineralogist for the year ending (1883) (14591657407).jpg

Identifier: annualreportofst10cali (find matches)
Title: Annual report of the State Mineralogist for the year ending ...
Year: 1883 (1880s)
Authors: California State Mining Bureau
Subjects: California State Mining Bureau Mines and mineral resources Gold mines and mining Geology Mineralogy
Publisher: Sacramento : California State Mining Bureau
Contributing Library: University of California, Davis Libraries
Digitizing Sponsor: University of California, Davis Libraries

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s at Forest Hill, Iowa Hill, Deadwood,Last Chance, Canada Hill, Dutch Flat, and some deep channel workingsbetween Rocklin and the American River, varying from about $100 to$1,000 per linear foot of channel worked, and equal to a product varyingfrom about $500,000 to $5,000,000 per mile, it is evident that the amountof gold already extracted is but a trifle compared with the amountremaining in the ancient river channels and quartz lodes. GEOLOGICAL FEATURES. The reader will be assisted by reference to the Geological Map andaccompanying profiles and sections through Placer County. No. 1 showing cross-section beginning at the Sacramento County lineand running along the line of the Central Pacific Railroad to Summit,thence east to the State line; and No. 2 from Colfax, running east alongthe township line between Townships Nos. 14 and 15 north, to the westboundary of range 11 east; thence northeasterly to the summit of BaldMountain; thence easterly through Tahoe City and Lake Bigler to the
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Sketch showing Sedimentary Formation near Lincoln. Placer County. by J.B.Hobson.E.M . PLACER COUNTY. 415 State line; also a sketch illustrating the formation developed by boringssoutheast of Roseville on the N.W. i of Sec. 9, T. 10 N., R. 7 E.,M. D. M. By reference to the accompanying sketch (Plate I) it will be observedthat the borings passed through about ten feet of surface soil, thencethrough alternate strata of clay, kaolin, auriferous gravel and sand, to adepth of about fifty feet; thence through yellow, pink, and brown clay,overlying a stratum of lignite, varying from four to twelve feet in thick-ness, underlying which is a bed of dark blue clay of unknown depth.The borings were sunk to a depth of ninety-six feet. The formation is similar to that found in the vicinity of lone, in Ama-dor County, and probably belongs to the Tertiary. The above forma-tion probably underlies that portion of the plains and rolling hillsimmediately west of the granitic rock. East of the sedimentary

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