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Show 336 PERSONAL ADVENTURES them. Some of the different ingredients that enter into the composition of the granite, or diorite rocks, are more easily decomposed than the others; this causes a vacant space or chink to be forn1ed in the rock, which then receives the rain or melted snow. When the te1nperature lowers so much as to freeze the water lodged in these cavities, from the ice occupying more space than the water did, it acts as so many wedges of great power, which split off rnasses of the rock, that fall down into the river below. These n1asses, often containing gold in greater or lesser quantity, are carried down with the stream, undergoing friction in their passage, and at last becoming ground into gravel or sand, according to the rapidity of the stream, the distance they have been carried, and the impediments they have met with in their transit. The largest pieces are found near and in the talcose slate rocks, but the finer particles and scales have been carried down by the streams to the lowest part of the valleys, where they are mixed with sand on IN CALIFORNIA. 337 the surface, and to the depth of from four or five feet. The cotnposition of Californian gold, ac-cording to the best analysis, is- Gold . . . . . . 88·75 Silver . . . 8·88 Copper . . . . . 85 Siliceous residue . Loss . . . . . • • 1•40 12 100 " From the character of the deposit in which the gold is at present discovered, and the fact that the streams are quite clear, and do not carry alluvial with them," says a clever writer, " we may conclude that they are of ancient date, and that the disintegrating process is not going on rapidly. The specimens of gold obtained up to the present time confirm this theory, for they all exhibit a fused appearance; some have pebbles of quartz embedded in them, and some are amalgamated. These latter are about the size of duck-shot, proving incontestably the pre- VOL. I. Q |