GEOLOGY. 223 



earth's surface, covering the declivities, and even the summits of the 

 hills, as well as the bottoms of the ravines and valleys. The sandbars 

 of many of the mountain torrents are extremely rich in metal. Quartz 

 is believed to be the only substance with which the gold is intimately 

 connected. The gold of different localities varies very much in size. 

 That from the banks and sandbars of the rivers is- generally in the 

 form of small, flattened scales, and commonly it is found to be finer 

 the lower you descend the stream. That taken from the bottom 

 of dry ravines is mostly of a larger size, and occurs both in small par- 

 ticles and also in small lumps and irregular water-worn masses, from 

 the size of wheat-kernels to pieces of several ounces, or even pounds, 

 in weight. The black, ferruginous sand, which everywhere accom- 

 panies the gold, varies in fineness with the size of the accompanying 

 gold. 



The slate beds mentioned above often include dikes or beds of 

 quartz rock, in which some have asserted that gold has been found in 

 place, but this still wants confirmation. In some of the richest ex- 

 plorations yet made, however, the slate directly underlies the stratum 

 of diluvium menlioned as containing the gold, and this slate has many 

 crevices or " pockets," into which the gold has been washed in con- 

 siderable quantities, and this fact also has given rise to the belief that 

 gold has been found in place. 



There can be little doubt that the gold was deposited in its present 

 position by the same agency and at the same time as the stratum in 

 which it occurs. It is a peculiar fact, that some specimens have been 

 found which appear to have been moulded on regular quartz crystals. 



To the east of the gold regions are the mountains of Sierra Neva- 

 da, consisting of primitive and metamorpbic rocks. In the vicinity of 

 these mountains, the gold and its associated quartz disappear ; the 

 rocks underlying the drift appear to consist entirely of gneiss, which 

 is afterwards succeeded by granite. 



North of the Bay of San Francisco, talcose slates of various colors 

 have been noticed, and also hills of red and yellow jasper, in layers 

 varying from half an inch to four inches in thickness. At the 

 Straits of Caquines, bluffs of red sandstone, alternating with clayey 

 layers, occur. This sandstone, which is believed to belong to the 

 eocene period, is soft and easily worked. On a small island near 

 these Straits, gypsum has been found in considerable quantities. 



In a letter, dated at San Francisco, October 29th, and published in 

 Sillimari's Journal for January, 1850, received since the above was 

 written, Rev. C. S. Lyman states that " gold has at last been dis- 

 covered in place, in veins penetrating quartz beds, on the Moke- 

 lemnes and in the vicinity of the Mariposa and one or two other places. 

 I have this from gentlemen who have seen the veins, and who are 

 reliable witnesses. These veins are of course not worked yet, as it is 

 more profitable to dig the wash-gold." 



The Pacific News for November 30th, states that " quartz containing 

 gold has been found in inexhaustible quarries through the whole 

 mountainous region which forms the western slope of the Sierra Ne- 



