106 SUEVEY OF COLOEADO AND NEW MEXICO. 



Copper glance^ (CngS.) — Bergen district, near Idaho City, Pleasant 

 View, &c. 



Malachite, {GnO .CO2;) Blue vitriol, (C11O.SO3+5HO ;) Green vitriol, 

 (CuO.SOa+THO.) — Occnr in various mines from the decomposition of 

 the pyrites. 



PyromorpMte, (PbO.POs+PbCl.) — ^Associated with the galena of va- 

 rious mines near the surface. 



Specular iron ore, (FeO.FcaOs.) — Cache a la Poudre, St. Yrain's, &c. 



Bed and hrotcn hematite, (Fe203andPe203+HO.) — Of frequent occur- 

 rence in the vicinity of the coal. 



Coal. — Beds of coal occur all along the flanks of the mountaiis, 

 but in the property of Mr. Marshall are perhaps the best exposures. 

 Here are no less than nine outcrops. They make their appearance at 

 various points along the range as far down as Santa Fe, and are of un- 

 known extent. Albprtine coal, or solidified petroleum, is stated by Prof. 

 Denton to occur on "White Eiver, in the western part of the Territory. 



Gold — Occurs in the neighborhood of Central City, in the German 

 lode, and many others. In the Placer diggings. Some beautifn-; crys- 

 tals attached to cubes of iron iJjTites in the ore from the Pleasait View 

 mine. 



Silver. — In many mines as wire or hair silver, Brown auc. United 

 States Coin lodes. 



Cerussite, (PbO. CO2.) — Pleasant View mine. — In small tjanslucent 

 crystals occurring in geodes. 



Anglesite, (PbO. SO:,.)— Freedlandlode, Trail Eun. 



Horn silver, (Ag CI.) — Georgetown, Siuike Eiver. 



EmhoUte, (AgBr-f AgCl.)— Pern district, Snake Eiver. 



Titanic iron ore, [x TijOj+j/ Fe203.) — Quartz Hill, and Eassel Gulch, 

 near Central City. 



Micaceous iron ore, (FeaOy.) — Elk Creek. In fine crystds like mica. 



Spathic iron ore, (FeO . CO^.) — Eureka and Griffith lodfs, &c. 



Smithsonite, (ZnO . CO2.) — Eunning lode, Blackhawk, <fcc. 



Salt, (XaCl.) — From Salt Springs in South Park, tweity miles south- 

 east of Fairplay. Can produce fort}' thousand i^oundsi^er diem. 



By characteristic minerals, I mean to include all tluse that have no 

 commercial value. They furnish proof, in most case^, of the presence 

 of other minerals, of rocks or of formations. Of the characteristic 

 minerals, among the most common are — 



Hydrated oxide of iron, (broAm ochre, yellow ochre, bog iron ore, &c.) — 

 Occurs with the coal beds at South Boulder, Colder City, &c., &c., and 

 is frequently regarded as a surface indication of tie presence of gold, 

 silver and the precious ores generally. 



Quartz, (Si03.) — The most important of the claracteristic minerals. 

 Very widely diflused. Forms the gangue of nealy all the veins of the 

 precious metals in Colorado. As gangue rock i; crops out on the hill 

 sides in white or colored streaks, usually interse<ting the planes of strati- 

 fication of the rocks. Uncrystallized, in^esentin^^ sharp and jagged edges, 

 and a broken couchoidal uneven fracture, sou«times weathered by the 

 disiutegratiou of the minerals it contained Pebbles and partially 

 rounded crystals of quartz are abundant ir the i^rairies east of the 

 Eocky Mountains, whence they have been carried down, and may be 

 observed hundreds of miles east of the eastenmost " hog-back." Indeed, 

 the abundance of these small pebbles of qiurtz and of the red feldspar 

 is very remarkable, occurring as they dc in great quantities on the 

 summits of the little prairie hillocks at sich an immense distance from 

 their place of origin. 



