MAMMOTH LEDGE. . 243 



to the time I left the district (August 1), and Newton's Fork was compara- 

 tively untouched, the whole attention of myself and miners being given to 

 practically testing the value of the richer deposits situated some miles below. 

 While I am writing hundreds of miners are hard at work prospecting this 

 region, and the valuable deposits, wherever they exist, will soon be found 

 and made to give up the gold they contain and have held uselessly locked 

 up for ages. At this period in the exploration I was camped with a small 

 party of my miners about a mile below the junction of Spring Creek and 

 Newton's Fork for several days. We had been prospecting the head 

 branches of the stream with results which were not as encouraging' as the 

 appearance and character of the gravel deposits would indicate should be 

 obtained. 



The mountainous region to the north and east, embracing the valleys 

 of Spring and Rapid Creeks, was unknown and unexplored. The expedi- 

 tion led by General Custer the preceding summer had passed around this 

 rugged area to the west and north, following the valley of the Box Elder, 

 on leaving the Hills, and the miners who were on French Creek had not as 

 yet attempted to penetrate it in search of gold. 



I had noticed to the east the change in the geological formation of the 

 country, and regarding the belt of clay slates and quartzites as more 

 favorable to the production of valuable placer-dejDosits of gold than the 

 metamorphic mica-schists with their superabundance of crystalline quartz, 

 I decided to descend the stream far enough to insure the concentration in 

 the placers of any gold resulting from the denudation of the ledges in the 

 slate formation, and there prospect and test the richness of the gravel 

 deposits and prove the value of the district. 



Locating in the valley of Spring Creek, about eight miles below New- 

 ton's Fork, near where the immense quartz formation known as the Mam- 

 moth ledge crosses the gulch, a few hours' prospecting resulted in the 

 discovery of gold in paying quantities in the placer deposits of this stream. 

 June 29, 1875, Thomas H. Mallory, one of the best prospectors associated 

 with me the past season, noticed a line of large bowlders extending across 

 the stream, forming a dam or riffle, and, suspecting that rocks of that 

 size and weight must rest on bed-rock, waded into the creek, and turning 



