GEOLOGICAL SURVEY OF THE TEREITORIES. * 171 



tant, to the west of tlie Eio Grande, are numerous isolated mountains 

 showing' the igneous protrusions. 



Taos Valley, therefore, forms a sort of half circle, and the mountains 

 which surround it, of which there appear to be ten or twelve distinct 

 ranges, are expansions of the main range. It is near this expansion 

 that the Moreno mines are situated, which have already proved unusu- 

 ally rich, and will probably continue to yield large returns of gold for 

 many years to come. 



On the sides of the mountains immediately opposite the Morena Val- 

 ley, north of Taos, are located the mines of the Arroyo Hondo Mining and 

 Ditching Company, of which Mr. Lucian Stewart, of Taos, is the superin- 

 tendent. Mr. Stewart has already erected a twenty-stamp mill on the 

 San Antonio Creek, and the supply of water is so great that if the mines 

 turn out to be rich in gold, the enterprise will prove a complete success. 



About twenty lodes have been prospected with more or less encour- 

 agement, and some of them look well. In, most instances the country 

 rock has a greenish ashen tinge, doubtless due to the influence of heat 

 from the igneous rockfe. The lodes are not very well defined ; one lode 

 has a strike a little west of north. It contains carbonate of copper, sul- 

 phurets of copper and iron. It was first prospected for silver, but turned 

 out to be richer in gold. The cleavage walls are lined with sulphate of 

 lime. The gangue roclc is mostly feldspar and quartz highly ferruginous. 



The main lode of the company is situated about half way up the south 

 side of the mountain. Dij) of vein, thirty-five degrees, strike nearly 

 east and west, inclining about south. The country rock is mostly 

 quartz, quite hard, while the seam, which is pretty well defined, is rotten 

 quartz. It is eight to twelve inches wide, and is called the " pay streak," 

 although the neighboring rock pays well. There may be a very wide crev- 

 ice here of which the walls have not been discovered. The cleavage lines 

 are well shown, and are of two kinds, one set dipping south thirty-five 

 degrees parallel with the ore streak, aud the other inclining north twenty 

 degrees. The principal lines of cleavage contain the rich ore. The 

 dip of the country rock is plainly south or southeast at a very high 

 angle. A tunnel has been excavated into the side of the mountain five 

 feet in diameter, and one himdred and eighty feet deep, two hundred 

 feet below discovery point. 



Ail along the sides of the mountains are quite thick, deposits of recent 

 material, as clays, sands, and marls, and at one locality, while digging a 

 ditch, Mr. Stewart discovered a thick bed of aluminous clay which con- 

 tained much gold, but it was found to be so diificult to extract it that 

 the placer was abandoned. The sides of the mountains everywhere are 

 covered with "diggings," where the Mexicans in former times washed 

 the loose drift with water, obtained by melting the snows. 



These mountains are composed largely of gray granite, and the reddish 

 feldspar is not much seen. Each one of these ranges seems to afford a 

 good example of an anticlinal axis, the sides being shown by the shape of 

 their slopes, which are very seldom symmetrical, one side of the anti- 

 clinal being much more prominent than the other. 



From Taos to Eio Colorado the foot-hdls of the mountains are covered 

 with pifion^ \nt\\ a few larger pines which v^^ould make excellent timber. 

 Indeed, I am inclined to "the opinion that the basaltic mesas are the 

 natural habitats of the pinon, which is a low scrubby tree, fit only for 

 fuel, while the larger species of pine and spruce are found growing on 

 the metamorphic rocks. 



As we approach the Eio Colorado the outbursts of basaltic material 

 increase. The Eio Grande and its branches, before they join the larger 



