54 



GEOLOGIC GUIDEBOOK ALONG HIGHWAY 49 



[Bull. 141 



quartz-ankerite rock containing both free gold and gold bearing sulfides. 

 The wall rocks are Calaveras schist and serpentine. The total depth is 

 1845 feet via shaft and winze. Probable production is in the neighborhood 

 of $6,000,000. 



Four-tenths of a mile north of Jamestown a road which leads to 

 Shaws Flat joins Highway 49. Shaws Flat is accessible from Sonora and 

 Columbia also. The town was founded in 1850 but the rich placer diggins 

 of the Shaws Flat-Sonora district were discovered in the summer of 

 1848. As at Columbia, which is but a few miles to the north, the Calaveras 

 limestone underlies most of the diggings and has an extremely rough, 

 hummocky, crevassed, potholed, surface, caused by surface leaching of 

 ground water and probably accomplished, for the most part, since the 

 gold was deposited. Much of the gold was found in the red, weathered 

 clay of the limestone, and not directly on the bedrock. Some of the Eocene 

 gravels which once covered the limestone surface can be seen, but they 

 are scarce because they were probably stripped off this surface by 

 erosion long before the days of 49. Although exceedingly rich, the Shaws 

 Flat deposits were very shallow and were soon worked out. The source 

 of the gold from these early rich placers may well have been close by ; 

 for north of Sonora on the road to this area is a hillside covered with 

 early pocket mines. No accurate breakdown on the production of Shaws 

 Flat, Whimtown, and other diggings in the Shaws Flat vicinity are 

 available, but it is probable that part of the $87,000,000 credited to 

 Columbia came from diggings to the south. Some of the channels of this 

 district were followed partly under Table Mountain, separated from it 

 by deposits of andesitic cobble. 



Between Jamestown and Sonora, the countryside becomes more hilly 

 and is rather well forested. There are several resorts and picnic spots 

 along the highway and several nice stands of pine timber. The rocks 

 along the way are Calaveras schists and greenstones of no particular 

 interest. 



Sonora, one of the larger foothill towns and county seat of Tuolumne 

 County, was founded in 1848 by Spanish Americans. It is a nourishing 

 and attractive town with its yellow frame County Courthouse and rustic 

 red St. James Church. Sonora boasted a newspaper as early as 1850. The 

 Holden Chispa nugget which weighed over 28 pounds was taken from 

 diggings within the present city limits. An excellent collection of gold 

 specimens may be seen at McKibbens Mountain Cafe on the main street 

 of town. Historical Marker 139, placed there by the American Automobile 

 Association and State Division of Highways commemorates St. James 

 Church, and the Tuolumne County Chamber of Commerce has erected 

 a monument to the early pioneers of the city located at the divided part 

 of the main street through town. Sonora is the gateway to the Pine Crest 

 resorts and Sonora Pass in the High Sierra. 



Two miles northwest of Sonora, the turnoff for the famous placer 

 mining camp of Columbia is located. The short side trip to Columbia is 

 well worth the traveler's time. The town has not been modernized and 

 is in a fair state of preservation. The vicinity of Columbia has recently 

 been made a state park. St. Ann's Church, a red brick structure located 

 to the south of town, has all of its old charm. The search for gold is said 

 to have stopped at the church grounds and remnants of the gold gravels 

 supposedly lie untouched beneath the church. The rough limestone bed- 

 rock, which is much like that at Shaws Flat, is credited with having 

 caught and held gold to the fabulous sum of $87,000.000. Few if any gold 

 placers of similar area have yielded so rich a harvest ! Several very large 

 nuggets were taken from the Columbia diggings. A slab-shaped mass 

 found on Knapp's Ranch weighed over 50 pounds avoirdupois, and 

 $8,500 in gold was recovered from it. Another from Gold Hill weighed 

 362 troy ounces valued at $6,500. Two others were valued at $5,265 and 

 $5,000 respectively. The town contains many interesting buildings, a 

 local-color museum, and a sweetshop par-excellence. State Division of 

 Highways Historical Marker 123 marks the turn onto Columbia 's main 

 street. 



After leaving the vicinity of Columbia, Highway 49 bends around 

 the northern end of Table Mountain and follows along its western base 

 for about two miles before turning west into Tuttletown. Some of the 

 gravels in the creek beds of this vicinity are being worked for gold by 

 small dragline dredges. Tuttletown, located seven miles from Sonora via 

 Highway 49, was first settled by Mormons in 1848, and was originally 

 called Mormon Camp. James M. Tuttle, whose name the town now bears, 

 arrived considerably later than the first Mormons. A fairly well pre- 

 served stone structure dating from 1852 is one of the few relics remaining 

 in old Tuttletown. Division of Highways Historical Marker 124 is 

 located near this spot. The headframe and red sheet iron buildings of 

 the Arbona mine are located close to the highway near the center of 

 Tuttletown. The mine has a 600-foot inclined shaft in schist country 

 rock. Production from this mine has not been extensive and there has 

 been no major exploitation since 1909. Some pocket gold was recovered 

 from it during the early thirties. 



State Division of Highways Historical Marker 138, one mile from 

 Tuttletown, is close to the turnoff to Jackass Hill. Jackass Hill was once 

 famous for its "pocket" gold mines and has since been made a shrine to 

 to the memory of Mark Twain who stayed there with the Gillis Brothers 

 for an indefinite period. The present Mark Twain cabin is a reconstructed 

 replica of old cabins in the area and is not the original Gillis cabin. No 

 production figure is available for the mines on Jackass Hill, known gener- 

 ally as the Chileuo group, but some of the pockets were exceedingly rich. 

 The gold occurs in quartz and carbonate stringers cutting Calaveras 

 schist. The Jackass Hill mines produced beautifully crystallized speci- 

 mens of gold as well as the gold tellurides petzite and calaverite. 



