The new silver mines lie just north of the San Diego County line, and west of the divide, a position which brings them into Orange County. The formations in which the veins occur vary from a dark brown felsite, often micaceous, to a finely banded quartzose rock. The latter is very compact, and often almost massive. In places hard, blocky argillites appear. The two or more veins found here carry galena bearing silver, and also much magnetite and iron sulphurets, with some of the baser metals. The veins are characterized by a dark red gossan cap on or near the surface. Carbonates are found in this. These deposits exist as impregnations along a fissure, which is not very strongly pronounced. The ore is usually quite massive. The little gangue present is calcite. Not enough development has been made here at the time of my visit to show how extensive the deposits are. The metamorphic rocks extend north along the mountains, forming the summit and eastern slope for a number of miles. Granite borders them on the west toward San Juan. It is probable that this belt of mineral-bearing rocks runs continuously through to Silverado Cañon. At some time this Elsinore basin opened out through the Temescal Valley, but now a low divide separates it from the head of Temescal Creek. Gravel-topped hills lie along the mountains west of the creek. At the terra cotta works a drill was sunk over 600 feet without reaching the bottom of the basin. The Cheney Coal Mine is located 5 miles northwest of Elsinore, in the same basin. The beds dip to the west and southwest, having clay below, and sandstone followed by clay above. The coal is 7 to 8 feet thick, generally solid, but in places showing a parting in the middle. A great deal of faulting has taken place, but there seems to be no system about it. The throw of the faults sometimes amounts to 30 feet, often disturbing the pitch of the vein, and making it greater. The strata evidently belong to the Miocene-Tertiary, for a little farther down the valley fossils of that age are found. This old Tertiary valley, undoubtedly an arm of the sea, opened into the large valleys of San Bernardino and Los Angeles Counties, and extended southerly to Temecula; though south of Elsinore the Tertiary is covered by Quaternary gravels. The depth is unknown, but the width is quite narrow, being from 1 to 2 miles. Not more than a quarter of a mile northeast of the coal mine the metamorphic rocks, quartzites, and hard, blocky argillites outcrop. East of Temescal Creek northward the mountains are formed of a quartz feldspar porphyry of a dark gray color; at times it blends into portions not distinctly porphyritic.