PEALE.J 



GEOLOGY CATALOGUE OF MINESALS. 2G9 



plilogopite^) near Mount Lincoln and Mount Bross, especially near 

 the junction of the sandstones and schists ; biolite in the granites of the 

 Elk Mountains and in the rocks of the various dikes in that range ; 

 muscovite cooimou in the foot-hill range, along Tarryall Creek and in 

 the Sawatch range ; brotcn variety on Buffalo Peaks ; gj-een variety in 

 schists east of Italia Peak, 



Molybdenite,* in thread-like veins on Silver Heels Mountain. 



Muscovite. (See Mica.) 



Obsidian, on Buffalo Peaks; chips in the Arkansas Valley aiid in 

 Union Park. 



Orthoclase. (See Feldsjfar.) 



Phlogopite. (See 2Iica.) 



Prehnite, in clusters of small crystals in trap in Mount Bross mining 

 district. 



Pseudomalachite, in gray argillaceous slates at the bend of the Little 

 Platte Eiver, south of Fair Play. 



Pyrite, in all the gold and silver mines of Buckskin Gulch, invariably 

 auriferous, but seldom enough to be valuable ; massive in simple cubes 

 and pyritohedrons; (perfect cubes of four to five inches are found in 

 the Philips mine*,) on Italia Mountain in small octahedral crystals 

 near the base of Teocalli Mountain ; at White Eock Mountain 5 in the 

 mines of the Elk Mountain ; in a black flinty limestone on Eagle 

 Eiver opposite Eoches Moutonnes Creek. 



Pyrolusite,* massive in Buckskin Gulch and on Silver Heels Mountain. 



Pyroxene, in the limestones in the Mount Bross mining district. 



Quartz, in the granites of the foot-hill range, the Sawatch range, and 

 the Elk Mountains. Eock crystal, in the granites and in the sandy 

 debris on the Colorado divide ; at Pike's Peak 5 in the limestones of 

 Mount Lincoln and Mount Bross and Horseshoe Mountain ; in the 

 Cretaceous shales on East Eiver ; on Massive Mountain ; in the mines 

 of Elk Mountain district at head of Eock Creek ; on Sopris Peak ; 

 Homestake mine near Tennessee Pass. Amethystine, on Eock Creek ; 

 Eose, near the head of Granite Creek ; smolcy Cairngormstone ; 

 on the Colorado divide ; on Pike's Peak ; near the Platte Canon 

 in fine large crystals ; on Massive Mountain. Milky, on the Colorado 

 divide in caiion of the South Platte ; near Mount Howard on Granite 

 Creek ; on Massive Mountain. Chalcedony, in South Park east of Fair 

 Play ; near Buffalo Peaks ; on Frying-Pan Creek ; in the small park 

 at the head of Trout Creek near the salt-works southwest of South 

 Park. Agate, in South Park on Fryiug-Pan Creek ; in the Arkansas 

 Valley in the park at the head of Trout Creek ; on the butte east of 

 the salt-works. Basanite, on the butte east of the salt-works in 

 South Park. BiUcified tvood, at petrified stumps near Florissant. 



Ehodochrosite,* (crystallized,) in the gangue of the Diadem mine, 

 Buckskin Gulch. 



Eipidolite, on Sopris Peak, near Eed Eock Pass, at the head of Lake 

 Creek. 



Eutile,* in veins of quartz traversing the limestone in Ute Pass. 



Sanidine. (See Feldspar.) 



Satin spar. (See Gypsum.) 



Selenite. (See Gypsum.) 



Siderite,* (crystallized,) at the Sweet Home mine and many places in 

 South Park. 



Silicified wood. (See Quartz.) 



Silver, (native,) in nuggets, wire, and thin scales iu the mines around 

 Fair Play; iu Washington Gulch, in the Elk Mountains; in the 



