The Arizona sentinel., 1900-11-14
CASTLE DOME DISTRICT.

The veins Of the Castle Dome district may be said to have been redscovered in 1S63 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 depth of from 6 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-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, 1870. Up to January l, 1s92, 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 a 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 noted landmark, being visible from a great dis tance in all directions. It was originally called Capitol Dome by the officers at Fort Yuma in 1S5n from inc fancjed reCero hlence tn the doTna 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 it's 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 a depth of 800 feet or more. The veins are re- markably regular and well formed The ore is galena, carrying about 30 ounces of silver to each ton. The veins trend in general northwest and southeast course and are nearly vertical. The outcrops are in- dicated by outlying masses and weather worn crystals of f1ourspar. which is the chief veinstone. Calcite and gypsum are also found, and in some of the veins there is vein- stone OI Qu1TGL Sp6IScu III SneeUS or 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 feet, sometimes from to 12 feet wide. There are veins also only few inches in width. In general the veins 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 feet thick was found.
 At or near the water level, where the galenite has decomposed, both carbonate and sulphate of lead are found associated with pale-green fluOrite and an abundance of crystallized yellow wulfenite, another occurrence giving evidence of the presence of molybdenum in galenite.
 The rocks of the district are compact fine grained mica and clay states standing nearly on edge and traverSed by numerous dikes or intru- sive masses of chocolate-colored porphyry.