114 RECONNAISSANCE FROM CARROLL, MONTANA, 
Musselshell, is a clay-slate, of which there must be a very great thickness, interstratified with some 
sandstone-beds. The central portion of the range is trachyte, which is very abundant, forming a 
series of high hills and seriously interrupting our observations in the succession of the strata. 
Occasional outcrops of sedimentary rocks, principally slates and shales, appear; but as they 
contained no fossils, and as their succession was everywhere interrupted by the trachyte, their 
relations to what had preceded remain very uncertain. On the whole, the caiion gives a very 
fair exposure of the successive rocks, and to one who could do more than take passing notes in 
riding through it would no doubt yield some important facts. 
Leaving the cajion, we emerge into an open rolling country, covered with grass, and with few 
exposures of the underlying rock. This, as far as could be observed, was a yellowish fragmentary 
slate, with occasional veins of quartz and calcite. A number of openings have been made by indi- 
viduals prospecting for metal, but only faint indications of copper were observed. At Copper- 
opolis, a mine has been sunk some 40 feet into this slate, and some very fair copper-ore and a little 
silver ore are being taken out. The mine is being worked on a very small scale indeed, only two 
men being engaged in it; but the ore obtained is sufficiently valuable to pay its way to the Hast, 
where (at Baltimore) it is smelted. 
Near this point we pass the divide, and descend rapidly to the valley of Deep Creek, leaving 
the Musselshell behind us, and striking waters that flow into the Missouri near Sun River; that is 
above Fort Benton. 
The valley of Deep Creek, though here somewhat narrow, becomes rapidly wider as we follow 
it down to Camp Baker. It is a fertile alluvial plain, and is no doubt susceptible of successful and 
profitable cultivation. There is as yet, however, no market for cereals in the vicinity, and the 
grassy meadows are given up to large herds of cattle, which range at will over the valleys and 
foot-hills. Every settler owns some cattle and horses, and these require little or no care, even in 
winter. The inhabitants state that they cut no hay for the winter-consumption of their stock, nor 
do they build stables or shelters for them at that season. The animals are said to run out all 
winter and to keep fat on the standing hay. Montana beef has quite a reputation for excellence 
west of the Missouri, so that the raising of cattle is likely to prove the most profitable pursuit for 
the settler until railroads shall have supplied him with a market for other products. Deep Creek, 
like most of the streams in this neighborhood, abounds in delicious troutand grayling (Thymatlus), 
both of which attain a large size, sometimes weighing three pounds and more. 
To our left, as we come down the valley of Deep Creek, we have the Elk Range high above us, 
the summits of which consist of trachyte. This has taken many curious forms, as pinnacles and 
towers, which rise above the timber, and give to the hills a very castellated appearance. An out- 
crop of purplish-red slate to the left of the road, and dipping 40° southerly, deserves to be men- 
tioned, as its exact counterpart was seen at Camp Baker, sixteen miles distant, there overlying the 
Potsdam limestones. To the right, that is west, were a series of limestone ridges with masses of 
trachyte interstratified. These beds of trachyte have all the appearance of sedimentary rocks at 
a distance, so entirely do they conform to the uptilted beds of limestone. These latter have a dip 
of 40° to the southwest. They have the appearance of the Potsdam limestone beds just spoken of 
as occurring at Camp Baker, and since, if continuing, their strike would make them appear there, 
it is hardly to be doubted that they too are Silurian. 
The Sulphur Springs are about 17 miles from Copperopolis, and lie at the point where the road 
to Camp Baker turns at a sharp angle to the west. The springs have a temperature of 150° or 
thereabouts, and are strongly impregnated with sulphureted hydrogen. They are quite well known 
through the Territory, and are believed to have the beneficial effects generally ascribed to similar 
springs, and to be especially valuable in cases of rheumatism, a complaint very common among 
miners. Considering the vast trachytie upheaval which has taken place in that vicinity, the pres- 
ence of hot sulphur springs can hardly excite surprise. 
From the Sulphur Springs, the road continues west, at the foot of the Big Belt Mountains, cross- 
ing a wide grassy plain, which has an even, uniform slope up to the edges of the hills. The stream, 
some ten miles from the springs, where Newland Creek joins it, runs through a gorge of por- 
phyritic trachyte with a distinct columnar structure. This rock borders the creek for some dis- 
tance, and the dike runs across the road, continuing on in a northerly direction. From here a 
