282 GEOLOGY OF THE BLACK HILLS. 



a pennyweight was obtained from one of their prospecting pits near Camp 



Terry. Gravel dei)0sits of considerable extent are reported in the valleys 



of the l)raiiches of the east fork, but have not as yet been prospected by 



the miners. The area drained by this fork is more open and less rugged 



than the territory to the west, resembling the Elk Creek district, wliicli it 



adjoins. Gold has been discovered by the miners on Deadwood and ^Vliite- 



wood Creeks and the numerous gulches running into them in the vicinity 



of Terry Peak. 1'lie placers are quite extensive, and in most places the 



bed-rock is reported to be n^eftr the surface, and the gold is doubtless 



derived from the disintegration and erosion of the igneous rocks as well 



as from slates and quartzites. 



Having detected gold in similar trachytes in the Bear Lodge range, 



I consider its occuiTence in rocks of iji-neous origin in this district as 



extremely probable. The following letter from Mr. T. H. Mallory, formerly 



one of my assistants in prospecting the gold field, gives the result of his 



explorations on the branches of Bear Butte Creek since the return of the 



expedition : 



Hill City, Dak., January 31, 187G. 



Dear Sir : Botsford and I liave just returned from a trip to the north. We 

 made locations on Whitewood, a large stream that rises around the northeast side of 

 Terry Peak and runs down to the Belle Fourche. Starting from the poiut where the 

 creek runs into the lowlands not of the caiiou, forming bars, up it to the west fork, or 

 Deadwood, as it is called, there are no better paying mines for a poor man in the Hills. 

 The ground prospects in the creek and on the bars, all the way down to bed-rock, an 

 aAcrage of about two cents to the pan in line gold. It is said to be the same on Dead- 

 wood. The length or extent of locations on these creeks begins at the mouth of Whitc- 

 Avood, and then running thence up Deadwood, makes a distance of twenty-five miles, 

 all good mining ground. 



A small gulch running into Deadwood,' called Black Tail, is said to be good. 

 These mines will certaiidy pay from $10 to an ounce a day to the man when worked in 

 the spring. They are easily opened, for the bed-rock is not deep, like it is on Spring, 

 Castle and Kapid Creeks. 



T. H. MALLORY. 



W. P. Jenney. 



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