146 A Bibliography of the Geology, etc., of California. 

 Beechey, Capt. F. W. Narrative of a voyage, etc. 



"The cliffs of the main land, opposite the northwest shore of the 

 Island of Los Angelos afford masses of actynolite and beds of mica 

 slate and talc slate. 



"The Island of Molate, about four miles north of Los Angelos, 

 appears at a distance to be of a red colour, and contains much red 

 jasper, and in a small portion of the cliff black ferruginous 

 slate.— C. 



"In the Island of Yerba Buena, the perpendicular cliffs west of 

 the bay are formed of clay-slate at their base, whilst the superin- 

 cumbent rock is sandstone, for the most part in angular masses, 

 and without distinct stratification. The clay-slate is much con- 

 torted, arched, and wavy, assuming an east and west direction, and 

 dipping chiefly to the south at a considerable angle. The sand- 

 stone shows itself in the point that forms the eastern part of the 

 bay. 



"The rounded hills of the peninsula on which the Presidio of San 

 Francisco is placed, are variously formed of sandstone, loose sand, 

 serpentine, flinty slate, and jasper. The westernmost hill, which 

 rises from the sea between the fort and the Punta di los Lobos, is 

 serpentine. The north declivity, on which the quadrangle of the 

 Presidio is built, is sandstone. To the eastward of this the serpen- 

 tine again forms a hill of equal if not greater height. The hill to 

 the westward of the Mission is serpentine. That which rises to 

 the south of it exposes a bare and scarped brow of flinty slate and 

 jasper. Rocks of a similar nature protrude through the surface of 

 the soil of the hills which separate San Francisco from the exten- 

 sive valley of Santa Clara (Las Salinas), about six leagues to the 

 southward. These hills are called Sierras di los Sambumos, and 

 terminate on the north in a rocky prominence, in the harbour east 

 of the inlet of the Mission. 



"The range of mountains, Las Sierras del Sur, which bound the 

 above valley to the south, expose flinty slate approaching to jasper, 

 a little northwest of Las Pulgas, and about eighteen miles east- 

 southeast of the Mission of San Francisco. Between the Missions 

 of Santa Clara and Santa Cruz, these mountains form four parallel 

 ranges, the two middle ones highest (about 1,500 feet), with steep 

 declivities ; the first two valleys are narrow ; the third is more 

 extensive, leading to the fourth range, which is considerably lower 

 than the others. The first two ridges are composed of serpentine 

 and a jaspery rock, the third principally of sandstone and occa- 

 sionally jasper, and the fourth, that nearest Santa Cruz, entirely 

 of sandstone, the upper part being mostly decomposed into loose 

 sand. Petrified bones of a cylindrical form were found in this cliff 

 of sand or loose sandstone in 1827. 



"Where this range approaches the road from Santa Clara to San 

 Juan, nearly half-way, the northern declivity is covered with frag- 

 ments of serpentine, and a little farther on is sandstone and flinty 

 slate. 



"In the neighbourhood of the Mission of San Juan is a sandstone 

 conglomerate, and on the road crossing from San Juan to the plain 

 of Monterey, is sandstone. From the interior of the range between 

 San Juan and Monterey, the inhabitants of Las Animas had brought 



