GEAVEL AND VOLCANIC FORMATIONS : IN PLUMAS COUNTY. 



217 



the tunnel, as well as a ground-plan of the locality, which are reproduced 

 on Plate K. There is a thickness of from sixty to eighty feet of detrital 

 material, covered by a mass of volcanic " cement/' breccia, and tufa, which 

 when least eroded away is about a hundred feet in thickness. At the bot- 

 tom of the detritus is a thick bed of pipe-clay with impressions of leaves, and 

 over this several alternations of gravel and sand (as shown on the section), 

 one of the strata of coarse gravel containing some gold. It is not likely, 

 however, that mining ever was, or could be, successfully carried on at this 

 locality. Of the theoretical bearings of the fact of the existence of these 

 deposits on Spanish Peak and Clermont more will be said in a future chapter. 

 There is a gravel deposit of considerable extent at a point on Spanish 

 Creek, above four miles west of Quincy, where consid erable work has been 

 done, although nothing could be ascertained with regard to the produc- 



tiveness of the material. 



From the large amount of washing which had 



been done here previous to 1866, it would appear that the undertaking had 

 been profitable. The thickness of the gravel was about seventy-five feet, and 

 it was quite homogeneous in character from the surface down to the bed- 

 rock. The locality has an elevation of about 400 feet above Quincy, which 

 itself is 3,270 feet above the sea-level. Consequently this gravel is about 

 8,400 feet below that on Spanish Peak. 



No extensive gravel deposits were being worked in 1866 in Plumas County, 

 north of the Middle Fork of Feather River, so far as the writer's observation 

 extended. In later years, according to Mr. Skidmore's reports to the Com- 

 missioner of Mining Statistics, there have been some undertakings of consid- 

 erable magnitude commenced at various points. One of them is said to be 

 •situated "near Quincy;' where the Hungarian Hill Company was at work 

 in 1873, preparing to introduce all the modern improvements in hydraulic 

 mining. This locality, the exact position of which is not specified, may be 

 the one mentioned just previously. At Ohio Creek, a small tributary of the 

 North Fork of the Feather, which enters that stream about six miles below 

 the lower end of Big Meadows, a dam has been built, for the purpose of get- 

 ting the necessary power to pump water up to an elevation of 328 feet, into 

 reservoirs, for the purpose of washing a (placer ?) deposit of gravel said to be 

 very rich in gold. 



Fourteen miles east of Quincy there is said to be an important placer-min- 

 ing claim, which from the description given must resemble in character the 

 so-called " seam diggings," previously mentioned as being extensively worked 



