124 SUEVEY OF COLOEADO AND NEW MEXICO. 



est) covered a space of perhaps 600 square feet, and emitted a vapor 

 wMch could be seen for a long distance. 



Surrounding it was a marsh or swamp in which salts from the evap- 

 oration were deposited. The temperature at the edges was perhaps 

 110° to 120° Fahrenheit, and bubbles of gas rise in many x)laces to the 

 surface, and are caused by the weight of a person walking around the 

 edges in the immediate vicinity of the soggy soil. Specimens of the 

 salts, as they lie loosely like an efflorescence, and also of the same ma- 

 terial in a harder form like California marble, (only not so variegated in 

 color,) were collected, but no opportunity offered to examine them. 



The surrounding country, and our road towards Homan's Creek, is for 

 miles covered with a white deposit called by the natives "alkali," sim- 

 ply. It gives the landscape the appearance of being covered with snow. 

 This "alkali" is probably composed of nitrate of x)otash, sulphate of 

 lime, and perhaj)s other salts in smaller quantities, but has not been yet 

 analyzed. The same deposit has been observed in the neighborhood 

 of St. Train's Creek, and in the basaltic region below Trinidad on our 

 route down to Santa Fe. 



Minerals observed in New Mexico. 



MliSTERALS OF C05IMERCIAL VALUE. 



Iron pyrites, copper pyi-ites. — Mostly auriferous. Widely distributed in veins over the 

 flanks of the Eocky Alountains, in New Mexico, and in numerous lesser chains of 

 granitic and metamorphic rocks. 



Malachite, gTeen vitriol, blue vitriol. — Principally from decomposition of the above, 

 wherever the ores have been exposed to weathering. Widely distributed in veins 

 over the flanks of the Eocky Mountains, in New Mexico, and in numerous lesser 

 chains of granitic and metamorphic rocks. 



Zincblende. — Often argentiferous. San Dia, &c. 



Galena. — Often argentiferous. Maxwell's, near Moro. 



Brittle silver. — Maxwell's, near Moro. 



Fahlerz. — Maxwell's, near Moro. 



Specular iron ore. — Eeal Dolores, near Ortiz mine. 



Eed and brown hematite. — Widely distributed. Old Placer, &c. 



Magnetic pyrites. — New Placer. 



Coal. — Eaton Mountains, Maxwell's, Eeal Dolores, &.c. 



Cerussite. — Maxwell's. 



Anglesite. — Maxwell's. 



Native gold. — Arroyo Hondo, Morena, Brahm Lode, New Placer, «&.c. 



Native silver. — Maxwell's. 



Horn silver. — Maxwell's. 



Titanic iron ore. — Eeal Dolores. 



Smithsonite. — San Dia. 



Silver glance. — Morena, New and Old Placers. 



Light and dark ruby silver. — Maxwell's. 



Spathic and micaceous iron ores. — Eeal Dolores. 



Tui-quoise, (2AI2O3 . POs-fSHO.) — Cerillos, between Santa Y€ and the San Lazaro 

 Mountains. 



CHARACTERISTIC MINERAXS. 



Quartz. — ^Forms gangue rock of most of the veins ; common. Agate, chalcedony, and 



silicified wood in the bed of the Galisteo. In the granites, gneisses, &c. 

 Hydrated oxide of iron. — Occurs with the coal beds, and colors the rocks near exposed 



veins, &o. 

 Opal. — Galisteo beds. 

 Feldspar. — Everywhere among the granitic rocks. Orthoclases predominant. Oligo- 



clases also abundant. Albite is found near Moro. 

 Labrador. — Basalt dikes, &c. 

 Hornblende. — Syenites, some basalts. 

 Potash and magnesian mica. — Gneisses and granites, and in the greissen found near 



Moro. 

 Leucite. — Trachytic lavas near Fort Union. 



