The Arizona sentinel., 1901-01-30
CASTLE DOME DISTRICT.

| The veins of the Castle Dome district may be
 said to have been rediScovered in 1865 for it was
 evident that they had been anciently worked, as
 already stated in the historical introduction.
 The metal had been taken out from many of the
 veins by the ancient miners down to a depth of
 from to 15 feet and in continuous lines of
 trenches, in some places for 50 to 100 feet or
 more These old workings were found to be
 safe guides to good metal bearing ground
 short distance deeper Well worn trails leading
 of from these pits to the banks of the Gila
 river, some IS miles distant, and the ruins
 there of some rude smelling furnaces, indicate | that the ores were carried to the Gila probably
 on the backs of Indians, and that they were
 Smelted there, whether by the AztecS or the
 early y-arriving Spanish explorer is not known. | Since 1863 these mines have been worked almost
 continuously, and are now yielding silverlead
 ore of most excellent quality, which is shipped | to San Francisco. The claims were worked by the prospectors without capital until October 1 1870. Up to January 1, 1892 there had not been an investment of over $500 in building or per
 manent Improvements The climate is such
 that men can work the year round without no more protection than is afforded by brush, huts or tents.
 The veins crop out on rolling plain or mesa
 at the base of the Castle Dome range, a very
 rugged and picturesque group of mountains trending northwest and southeast, rising near the center to the remarkable dome-shaped sum- init with precipitouS sides looking like a huge round castle or building with dome. It is a noted landmark, being visible from great dis tance in all directions. It was originally called Capitol Dome" by the officers at Fort Yuma in 1858, from the fancied resemblance to the dome of the capitol at Washington. This mountain range, being but sparingly watered, has never been convenient to prospect and very little is yet known of its structure or mineral value. The mines are usually reached from Yuma by driving to Gila City and thence to the mine, from Is to IS miles east and inland from the river. The claims are numerous. Some have been patented and worked to depth of 3O0H feet or more The veins are re- markedly regular and well formed. The ore is galena, carrying about 30 ounces of silver to each ton. The veins trend in a general northwest and southeast course and are nearly vertical. The outcropS are in dicated by outlying masses and weather worn crystals of 1ourspar. which is the chief yeinstone. Calcite and gypsum are also found, | and in some of the veins there is a vein- | stone of quartz dispersed in sheets or combs along the walls or in distinct sheets in the center. Manganese spar and barite are also as- Sociated in layers The thickness or power of these veins is usually from to 3 feet, sometimes from to F feet, wide. There are veins also ' only few inches in width In general the veins 1 are well filled with ore. This ore occurs in | sheets or punches scattered through the vein- | stone and commonly known among the miners | as ball metal. In one mine in the district mass of nearly solid ore 8 feet thick was found.
 At or near the water level, where the galeni:e ! has decomposed, both carbonate and sulphate 1 of lead are found associated with a pale-grecn | fuorite and an abundance of cryStallized yellow ' wulfenite, another occurrence giving evidence i of the presence of mOlybdenum in galenitc.
 The rocks of the district are compact fine grained mica and clay slateS standing nearly on edge and traverSed by numerous dilkes or intru- sive masses of chocolate-colored porphyry.