TOURTELOTTE PARK. 169 
ten horizontal drifts. Of these the upper ones find ore, and there is also 
some in the lowest or tenth level. The chief ore is associated with much 
barite and is thoroughly oxidized. It contains a great deal of. a bright-red 
powder, probably oxide of lead, often inclosed in barite crystals. ‘There is 
also, in blotches, a rich dark-brown stain, which is thought by local chemists 
to be an oxide of copper, and which is taken by miners as an indication of 
richness. There are a number of small east-west slips in the mine, along 
which ore appears to have made. ‘There are also some slight faults marked 
by breccia and open watercourses, which have formed subsequent to the 
ore deposition. 
Best Friend mine —T he Best Friend mine is situated a short distance directly 
south of the Little Percy, and has most of its workings on the Contact fault. 
The shaft runs down through porphyry, then through about 30 feet of shale 
to the Silver fault. In places in this mine the Silver fault comes down 
very close to the Contact fault, so that the two are separated only by a 
very thick limestone breccia. The Contact fault is marked throughout by 
a brecciation which is not very profound, and by a persistent seam of lime 
mud. This seam varies in thickness from an inch or two up to over 20 
feet. It is beautifully stratified, sometimes cross bedded, and when thickest 
is composed of fine lime mud alternating with coarse sandy layers. In the 
thickest portions this mud has evidently filled large caves. The stratifica- 
tion grows finer toward the top of this deposit, and on the bottom is a seam, 
which seldom exceeds 4 or 5 inches in thickness, where the fine clay is 
stained very black by oxide of manganese. A sample of this gave on 
analysis 45.86 per cent of manganese oxide, with 12.83 per cent of iron 
oxide. It was also assayed and found to be impregnated with silver to a 
certain extent. Above the mud seam is almost invariably limestone, while 
below it is dolomite; and the ore is nearly continuous with it, generally 
lying in the dolomite beneath. The width of ore is comparatively slight, 
the thickest pay streak in the mine thus far being only about 20 inches. 
In character the ore is similar to that of most of the mines in Tourtelotte 
Park, bemg entirely oxidized and containing much barite; and from the 
oxides of the metals it derives a general brown color, locally red or yellow. 
The following series of probable events in the history of the rocks in 
this mine may be inferred from the phenomena along the Contact fault: 
First, the formation of a fault which is parallel to the bedding, or 
