Miscellaneous Fuhlications. 145 



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



A map of the headland, embracing San Francisco Bay, accom- 

 panies this report. This is colored around the shores so as to indi- 

 cate the several formations ; serpentine, sandstone, and jasper rock 

 are represented. Lieutenant Belcher collected specimens of serpen- 

 tine on the west side of Angel Island. The occurrence of jasper 

 rock is also noted. 



The author, on page 174, gives the following account of the 

 geology of California, which was the first ever published ; it is given 

 in full, on account of its value : 



GEOLOGY, BAY OF SAN FRANCISCO. 



"The specimens collected in and near the Bay of San Francisco 

 consist of many varieties of common serpentine, bronzite, and as- 

 bestos ; clay-slate and mica slate, chlorite slate, horn-stone, brown, 

 green, and red jasper, and rolled blocks of glassy actynolite ; grey 

 sandstone, and imperfect wood-coal. The country near the port of 

 San Francisco is composed chiefly of sandstone, jasper, and serpen- 

 tine. Wood-coal is found in slight seams on the north side of the 

 entrance of the bay, and native salt near Santa Clara. Many of 

 the summits of the hills are composed of jasper, forming elongated 

 ridges, of which the general direction is north and south. This 

 jasper is succeeded by sandstone, of a loose texture, not effervescing 

 with acids, and disposed in every angle of stratification, occasionally 

 it is hard and of a blue cast ; it is frequently interrupted by abrupt 

 masses of laminated jasper in wavy stratification. The appear- 

 ance of the jasper, at its contact with the sandstone, is often very 

 remarkable. The jasper appears not to have acted on or displaced 

 the sandstone ; its exterior, for eighteen inches or two feet, is 

 usually rugged, and mixed with carbonate of lime, quartz, and 

 indurated clay ; its interior, however, presents a very beautiful 

 wavy disposition of the component laminae, a remarkable example 

 of which occurs at the Needle Rock, nearly opposite the fort. A 

 view of it is engraved at PI. Ill, Geology. It resembles an immense 

 mass of sheets of paper, or bands of list, crumpled and contorted 

 by lateral pressure. This contortion only occurs in the red jasper, 

 the yellow being seldom (if at all) stratified, but generally sep- 

 arated by cracks into rhomboidal pieces. A mass of at least one 

 hundred feet in thickness is beautifully stratified in short, wavy 

 lines, opposite the fort near Punta Diavolo, and rests on sandstone. 



"Between Punta Boneta and Punta Diavolo the sandstone is of 

 a bluish-grey colour, containing particles of coal. 



"The Island of Los Angelos is of very confused formation. Its 

 eastern side is sandstone, with occasional jasper rocks ; its western 

 side exhibits sandstone, conglomerate, clay -slate, and serpentine ; 

 its south side, bluish earth, (apparently decomposed serpentine), 

 and jasper beds containing red siliceous nodules, and much iron 

 pyrites. The superstratum of this island is almost entirely com- 

 posed of the debris of sandstone and jasper rocks, a little slate and 

 bluish earth, and betrays appearances of violence. It is about 900 

 feet above the level of the sea. — B. 



