656 IDAHO MINING DISTRICTS. 



in gold. Even supposing the admittedly uncertain production of the 

 first four years to be double the amount of estimates here given, the 

 total production would be only $62,000,000. 



While it is not possible to separate the production of the quartz 

 mines from that of the placer mines, it may be said with some confi- 

 dence that the total production of the former does not exceed 

 $4,000,000. 



TOPOGRAPHY. 



The Idaho Basin, the topography and geology of which are shown 

 in PL XCVI, is located in the middle of that great irregular mountain 

 mass extending between the Salmon and the Snake rivers. Defined 

 more closely, it is situated on the ridge between the north fork of 

 the Boise River and the south fork of the Payette. On the west rises 

 the Boise Range, the summits of which are visible from Boise, and 

 which attains elevations of from 7,000 to 7,500 feet. On the east rise 

 the irregular mountain complexes of Sawtooth Range and its pro- 

 jecting spurs. The basin occupies the head waters of Moore Creek, a 

 tributary joining the Boise River 10 miles above where it leaves its 

 canyon and enters the plains of the Snake River Valley. Ten miles 

 from its junction with the Boise River Moore Creek divides in two, 

 the westerly branch being called Grimes Creek. Five miles above 

 this the narrow canyon in which Moore Creek flows widens out to 

 a broad valley, in which the creek meanders with but little fall. At 

 Idaho City the creek branches again, and both forks head in the high 

 mountains near Wilson Peak and Elk Creek Mountain. A long ridge 

 with a southwesterly direction separates the Moore Creek Basin from 

 the depression of Grimes Creek. This ridge, which for a long distance 

 has a nearly level summit, rises to a height of 1,000 feet above Idaho 

 City. To the south and east of Idaho City the rise is much more 

 rapid. From the vicinity of Thorn Creek Mountain a number of very 

 high and narrow ridges project northward, encircling the southern 

 and eastern part by a chain of hills rising 2,000 feet above Idaho 

 City. Six miles above Idaho City, Moore Creek enters this rugged 

 complex of mountains, and 5 miles farther up heads in the precip- 

 itous amphitheaters of Elk Creek Mountain. 



The canyon of Grimes Creek reaches to a point 10 miles above its 

 junction with Moore Creek; then the valley broadens, exactly simi- 

 larly to the valley of Moore Creek, the main branch continuing in a 

 northeasterly direction and heading near Grimes Pass, 4 miles north of 

 Pioneerville. This, pass forms the water-parting between the Payette 

 and Boise rivers. It is comparatively low, attaining an elevation 

 of only 5,000 feet. Immediately east of Pionee.rville and of Grimes 

 Pass the high ridges of Wilson Peak and Summit Flat rise above the 

 more gently undulating country of the valley of Grimes Creek. An 

 important tributary, Granite Creek, enters 4 miles below Centerville 

 and extends in a northwesterly direction toward Quartzburg. Granite 



