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of the valley. The placers are mainly worked in the immediate vicinity 

 of the stream, whose waters are husbanded with greatest care. At one 

 of the lower mines, to which we were conducted by Mr. Keep, an old 

 and experienced miner, we had opportunity to examine the nature of 

 the "bed-rock", which had been laid bare over several square yards' 

 extent. Here it is composed of the partially-metamorphosed dark shales 

 of the Cretaceous, containing Inoceramus, &c., which dip to the north- 

 east at an angle of about 30°. The slaty shales were nowhere planed 

 smooth, their ragged upturned edges presenting innumerable "riffles", 

 between which the gold is lodged. Some of these "rims" afford very 

 rich "pay-streaks", and the entire surface, after having been laid bare 

 by the ground-sluice or hydraulic, both of which methods are here in 

 operation, is carefully gleaned for the auriferous earth. It is said that 

 the sources of these precious particles are readily recognized, the wire- 

 gold having been derived from the celebrated Aztec lode, while the finer 

 scales come from the Montezuma lode, the parent ledges which outcrop 

 in the eastern or southeastern flank of Great Baldy. 



Ascending Ute Creek some eight miles above its confluence with the 

 Cimarron, on either side of one of the steep gulches with which Great 

 Baldy is furrowed, are found the mines opened upon the Montezuma and 

 Aztec lodes. The former lode has a strike little north of east and south 

 of west, and along its discovered course it traverses a porphyritic rock, 

 such as apparently constitutes a great bulk of the eastern declivity of 

 the mountain. The Aztec, which is opened in the north side of the 

 ravine, about a mile distant, runs in a northwesterly and southeasterly 

 direction. At one of the lower galleries, which is being driven into the 

 hill with the view of penetrating to the lode, opportunity was offered 

 for observing the character of the deposits penetrated a distance of 100 

 lieet or thereabouts. The gallery penetrates the hill in a northeasterly 

 direction, probably nearly at right angles to the strike of the sediment- 

 ary deposits, and in the direction of their dip. At the entrance, and 

 extending several yards along the gallery, occurs a considerable thick- 

 ness of dark Cretaceous scales, which are changed to a brittle slate by 

 partial metamorphism, in which have been observed Tnoceramus, Ammo- 

 nites, &c. Then the excavation encounters a dark-gray quartzose rock, 

 the end of the gallery having reached a crevice, which was charged 

 with pyrite and fragments of partially-changed bituminous material. 

 The slaty shales at the entrance of the gallery are unquestionably Cre- 

 taceous, and it seems reasonable to infer that the quartzose rock may be 

 referable to the Tertiary formation, or the highly-metamorphosed sand- 

 stone occurring at its base; the changed bituminous seam representing 

 one of the thin lower lignite beds, such as are known to exist just above 

 the heavy-bedded inferior sandstone. 



The mines are opened at an elevation of about 9,500 feet above the 

 sea, thus showing that the Cretaceous shales have been tilted in the 

 upheaval of the Baldy range at least 3,000 feet above the level they 

 occupy in the borders of the plain at the mouth of the Cimarron Valley. 

 In the passage of the trail over the Blackhorse Pass, which diagonally 

 ascends the eastern declivity of the mountain to the saddle between 

 Great and Little Baldy for perhaps a distance of nearly a mile, rusty- 

 weathered fragments of porphyritic rock, apparently identical with that 

 inclosing the Montezuma lode, are met with, completely strewing the 

 surface. Above this nearly to the summit, a distance of half a mile, the 

 mountain-side is equally thickly covered with large and small angular 

 fragments of a schistose rock, the composition of which closely resem- 

 bles the quartzose ledge noticed in the Aztec tunnel ; and higher still 



