676 



IDAHO MINING DISTRICTS. 



Other small basalt areas were noted near Hawkins toll road, 2 miles 

 west of Star Ranch. This basalt forms a dike on the high ridge 

 between the toll road and Clear Creek, follows the road for some dis- 

 tance near longitude 116, and appears again on the ridge north of 

 the road. Here it is in part vesicular, and appears to have flowed out 

 from the dike. This basalt is probably also of Tertiary age. 



FINENESS OF THE GOLD. 



The fineness of the placer gold varies from 770 to 912. The follow- 

 ing list gives the value at some of the principal localities : 



Value and fineness of placer gold at principal localities. 



WATER SUPPLY. 



The water available for placer work is not abundant; in fact, usu- 

 ally the working season is only from three to four months. The 

 streams are not large and do not head among very high mountains, 

 so that the flood from the melting snows soon subsides. It would be 

 possible, but hardly practicable, to carry a ditch to the basin from 

 the headwaters of the Boise or the Payette. The principal ditches 

 are as follows : 



MOOEE CREEK. 



1. The upper Moore Creek ditch. Takes water from Moore Creek 5 miles above 



Gambrinus Gulch. Capacity, 600 miner's inches. 



2. The Lambing ditch. Dam below Illinois Gulch. Capacity, 350 miner's inches. 



3. The Christie ditch. Dam above mouth of Granite Creek. Capacity 1,100 



miner's inches. These three are on the northwest side of Moore Creek. 



4. Thorn Creek ditch. Takes its water from Thorn Creek, dumping it across the 



divide into Pine Creek; used for the high gravels south of Idaho City. 



5. Channel ditch. Dam on Elk Creek one-half mile above Elkhorn Mill. Capac- 



ity, 600 miner's inches. Covers divide between Elk and Grimes creeks. 



6. Mann's ditch. On south side of Elk Creek. Dam 1 mile above Forest King 



Gulch. Ten miles long. Covers Gold Hill at Idaho City. 



