78 



GEOLOGIC GUIDEBOOK ALONG HIGHWAY 49 



[Bull. 141 



North San Juan is one of the largest and best preserved of the 

 northern gold towns. The iron grillwork on the old brick buildings resem- 

 bles the grilled balconies of the Vieux Carre or French quarter of New 

 Orleans. North San Juan was founded about 1853 not by Spanish Cali- 

 fornians, as the name suggests, but by Christian Kientz, an immigrant 

 of German ancestry. He thought the hill resembled another known as 

 San Juan and named the new spot accordingly. 



NORTH SAN JUAN TO DOWNIEVILLE MAP 9 



The topography along Highway 49 north of North San Juan becomes 

 increasingly rugged and more and more typical of the higher Sierra. The 

 northward trend to the highway changes north of Camptonville and the 

 route follows the bottom of the tremendous canyon of the North Fork of 

 the Yuba in a broad northeasterly arc. Remnants of the Eocene surface 

 become more and more restricted in areal extent and are commonly 

 perched well over a thousand feet above present main-stream gradients. 

 Calaveras meta-sediments and thick sections of greenstones reappear 

 south of Camptonville and granitic rocks outcrop in only one area 

 between Camptonville and Downieville. Except for logged-off areas of 

 limited extent in the vicinity of North San Juan and Camptonville, the 

 entire region is heavily forested with coniferous trees. The fauna and 

 flora are typical of the upper transition and lower Canadian life zones. 

 The dominant forest trees are yellow pines and Douglas firs (Oregon 

 pines) with lesser numbers of white firs, incense cedars, and western 

 hemlocks. Alders and other water-loving trees grow along the water 

 courses. 



Two and eight tenths miles north of North San Juan the highway 

 crosses the Middle Fork of the Yuba at the Yuba County line. The grano- 

 diorite near the bridge is prominently jointed into rectangular blocks. 

 One tenth of a mile beyond the bridge, a dirt road branches off to the 

 east at an acute angle to the highway and recrosses the Yuba over a cov- 

 ered wooden bridge much like the one at Bridgeport. It is covered as a 

 protection against the winter snow pack and the tunnel-like appearance is 

 typical of old mountain bridges in this region. The road connects with the 

 famous mining district of Alleghany, located 24 miles northeast of the 

 turnoff . Alleghany can also be reached via dirt road from Goodyears Bar, 

 a few miles west of Downieville. Neither road is readily passable in wet 

 or snowy weather and a visit to Alleghany should only be attempted by 

 those used to back country roads. Lode, drift, and hydraulic mines are 

 located in the vicinity of Alleghany many of which have fine production 

 records. 



The Ruby drift mine is famous for its coarse gold nuggets and its 

 large quartz crystals. It is one of but few mines in the district which are 

 still operating. The workings are principally tunnels in the bedrock from 



which raises are put up to the channel gravels above. There are several 

 miles of tunnels and drifts and several vertical access and escapeway 

 shafts. Ore is hauled out along the main tunnel level and run through 

 sluices. More than 123 nuggets valued at over $100.00 each had been 

 removed from the Ruby by 1941. The largest weighed 52.3 ounces and 

 was worth $1,758.00. 



The best known lode mines in the Alleghany district are the Sixteen- 

 to-One, Oriental, Plumbago, Rainbow, and Bush Creek, all of which 

 have recorded productions in the millions of dollars. Dozens of smaller 

 workings have been profitable from time to time. The Brush Creek and 

 Yellow Jacket mines were operating early in 1948 as well as the major 

 Sixteen-to-One. 



The Sixteen-to-One, located a short distance downhill toward Kanaka 

 Creek from the town of Alleghany, has been the principal producer of 

 the district. It was discovered in 1876 and, as now operated, is a consoli- 

 dation of the Twenty-One and Tightner mines and several miscellaneous 

 properties. The main vein system lies along a reverse fault in wall rocks 

 of hornblende schist and other metamorphosed sediments of the Tightner 

 and Kanaka members of the Calaveras formation. Serpentine dikes cut 

 the Calaveras and both are cut by the thrust system. Vein minerals from 

 the Sixteen-to-One include arsenopyrite, mariposite, sphalerite, gold, 

 graphite, chalcopyrite, quartz, ankerite, tetrahedrite, galena, pyrrhotite, 

 and pyrite. The deepest part of the mine is 3300 feet from the surface as 

 measured along the inclined Tightner shaft. The total recorded produc- 

 tion of the Sixteen-to-One is slightly in excess of $16,100,000. 



Hydraulicking in the Alleghany district was confined to a few 

 favorable locations where the gravels were not deeply buried under the 

 Tertiary lava cap. Ferguson has estimated that between two and four 

 million dollars were extracted from the district by hydraulic means. 

 Something in excess of $10,000,000 was produced from drift mines such 

 as the Ruby and about $28,000,000 from lode mines. Placer gravels, prin- 

 cipally of Quaternary age added over a million dollars to the above 

 totals, giving a grand total of over $38,000,000 for all gold mines in the 

 district. Ferguson and Gannett give another interesting sidelight on 

 the richness of the Alleghany lodes. They compiled, from various author- 

 ities, a table of the probable amounts of gold eroded from the Alleghany 

 lodes and redeposited. in channel gravels below. These estimates ranged 

 from $18,000,000 to $52,000,000. 



The placer and hydraulic town of Camptonville is located half a 

 mile off Highway 49, 8.4 miles northeast of North San Juan. Campton- 

 ville was founded about 1850 as a hostelry on the Nevada City-Downie- 

 ville road. The town boomed as the result of local gold discoveries in 

 1852. Few present-day buildings date back to gold rush days as the 

 town was destroyed several times by fire. However, a quasi-colonial type 



