Geology and Mineralogy. 401 



and sixty miles in a southerly direction, turquoise has been found 

 in many places, notably in and around Hachita. All the locali- 

 ties are prehistoric workings and similar in the method of occur- 

 rence to those in the Burros. The nearest railroad station is 

 Separ, 22 miles north. All the surrounding region is very arid 

 and desolate. The writer had eight weeks work done there last 

 year and finally abandoned the region because of the scarcity of 

 the blue shades of turquoise and the natural regional disadvan- 

 tages (i. e., scarcity of water, etc.). 



What I particularly wish to announce is the occurrence of tur- 

 quoise, of fine color and quality, in a most unexpected locality, 

 i. e., in the Jarilla Mts. of Dona Ana Co., some one hundred and 

 fifty miles east of the Burros and two hundred miles south of the 

 Los Cerillos region. Here again the discovery was due to the 

 investigation of old-workings and the turquoise had passed as 

 merely " copper-stain." The ancient pottery and stone imple- 

 ments which the writer caused to be unearthed there, proved the 

 true character of the work and that the places had been aban- 

 doned for several hundred years. In the Jarillas, more than at 

 Hachita, the aridity and isolation of the place becomes a very 

 serious matter, since one must carry everything essential when 

 visiting the mines. The nearest railroad station is Las Cruces, 

 fifty miles west and El Paso, Tex., is about the same distance 

 south (in an air line). The Jarillas are a low range of mountains 

 about ten miles long and three miles wide (E. and W.) and rise up 

 out of a wilderness of sand. They are uninhabited, except by a 

 few wild animals, have no forest growths and no known springs 

 of water. The well-watered and well-timbered " Sacramentos " 

 are only 35 miles east, and it is but a day's journey from the deso- 

 late Jarillas to the habitable land? eastward or westward. The 

 vegetation is scarce and mainly cacti and palmias. In spite of 

 the isolation and the absence of water, a permanent mining camp* 

 has been established there and turquoise is being mined regularly. 

 There are at least ten places where some tribe of people have 

 worked for turquoise in past times; but all their work was very 

 shallow and stopped whenever hard firm rock was encountered. 

 Here the turquoise occurs in thin seams, cracks and crevices 

 which have a nearly vertical position. 



The trachyte is filled with long fissure-like cavities which are 

 lined with minute crystals of quartz, upon which are implanted 

 fine crystals of pyrite. Some cracks ot the rock are filled with 

 granular jarosite and gypsum coats some of the seams. A shaft 

 seventy feet deep has been sunk on a contact with the porphyry 

 and turquoise has been found all the way down. The associated 

 minerals are limonite and kaolin at surface and at the bottom 

 bright pyrite, chalcopyrite (rarely), gypsum, jarosite and kaolin. f 



*Xow known as the "Shoo-ar-me Mine of the Jarillas." 



fin one instance and at a distance of only 50 ft. from where turquoise was 

 being mined, a vein of rich copper sulphide was found, and as a rare association 

 some clear colorless crystals of wulfenite were observed that were hemimorphic 

 and also pyramidally hemihedral. 



