Other mines of the vicinity are the Topeka, Union, Escondido, King of the West, and Santa Clara, each of which has seen better days. The first three mentioned have been large producers, but are worked down to the water line, and a base ore proposition now faces the owners in the form of iron pyrites. IN THE MAIN RANGE. Up in the main range of the San Gabriel Mountains, on the north slopes of this rugged chain, are located a number of veins, on which considerable work has been done. The veins are well defined, ranging from 1 to 4 feet in width, striking northwest and southeast, and dipping uniformly to the northeast at a high angle. All of these veins contain gold, but all quickly run into sulphurets. All the mines are idle at present, but something brighter is hoped for. The sulphurets are said to contain sufficient gold to make chlorination profitable. If this is actually the case there is an abundance of material to work upon. LIPARITES AND TUFAS In the region about Acton are many hills of liparite (quartz-bearing trachyte) and tufa, which are identical with the rhyolites of the Calico region—the same violet-brown, porphyritic liparite; the same pea-green and buff-colored tufas; the same conglomerate; in fact, an exact facsimile of the Calico range. There are no great beds of sedimentary rock, however, and these liparite hills are comparatively small, isolated masses. As far as my knowledge goes ores of silver have never been found in these rocks in the Acton district. Careful prospecting may possibly discover such ores. PROSPECTS OF THE CAMP. Owing to the fact that the gold mines of this district have been worked to the water line, almost without exception, what now remains to be done to perpetuate the prosperity of the district, is to concentrate the sulphurets, working them by chlorination in works built in the district. Wood and water are both obtainable at moderate cost, and the sulphuretted ores of this district that contain but a very few dollars per ton should pay. The cost of mining, transportation, crushing, and concentrating should not exceed, ordinarily, $5 per ton of quartz, and the expense of treating the concentrates should be under $10 per ton. Base ores containing $10 per ton as it comes from the vein should realize a profit in this district, and I am told that many of the mines produce rock of a much better grade than that mentioned. SAN DIEGO COUNTY; ALSO ORANGE AND SAN BERNARDINO COUNTIES. By Harold W. Fairbanks, F.G.S.A.