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University of California . 



I Vol. 3. 



Comparatively coarse river gravel is exposed on the point 

 southwest of Bacon's field, including a boulder eighteen inches 

 long, but finer gravel appears again in a deep ravine north- 

 west of the field. The surface of the terrace is nowhere gravelly 

 but consists of red soil containing small fragments of slate 

 debris. 



Tennessee Flat, near Sims Gulch, has an extent of twenty- 

 seven and one-half acres, and an average altitude of 1,160 feet. 

 It has not yet been mined, but externally it presents the same 

 characteristics as Bacon Flat. On its inner border there is a dis- 

 tinct rise to the 850-foot terrace behind it, and on its outer border 

 a rapid descent of 200 feet to the next lower terrace. 



This terrace is such a sharp-cut and extensive bench that it 

 readily attracts the attention of one looking down on the basin, 

 and also is a prominent feature of the scenery to one coming 

 up the river. Back of Sandy Bar, one mile above Orleans, there 

 is an exceedingly steep slope of slate which has an even crest 

 600 feet above the bar, yet this crest is only the edge of Bacon 

 Flat. 



The 475-Foot Terrace. — The Orleans Bar Oold Mining Com- 

 pany is at present working off Brown Flat, about three-fourths 

 of a mile northwest of Orleans and immediately south of Sims 

 Gulch. The original extent of the flat was probably thirty-five 

 acres, of which about one-half is worked off. It is bordered on 

 the northeast by the slope leading up to Tennessee Flat, and on 

 the southwest by a gravel capped residual of the next higher 

 terrace. Between these bordering slopes it had a width of about 

 1,500 feet. The river, in forming the channels under it, must 

 have left the main valley and passed behind the residual just 

 mentioned, into what is now the valley of Camp Creek. The 

 surface of the flat is remarkably even, but slightly sloped toward 

 the south. It has a general altitude of 950 feet, or 475 feet 

 above the river at Orleans, but it is somewhat higher along the 

 north border. 



The bed-rock in the mine has a general altitude in the lower 

 channel of 880 feet, but slightly higher channels are being 

 exposed toward the north. They are all comparatively shallow, 

 and apparently about as wide as the present river. The bank 



