as well as those of the Gila and Salinas Rivers. The Apaches had arrows pointed with the same material. Yet I know of no other locality where obsidian is found in place in any of the regions visited by the Boundary Commission except this. All the specimens we saw were black, occasionally with a smoky or brownish tint.* We now continued our journey, and reached Mr. Osborne's at two o'clock. After dinner we rambled over the adjacent hills to obtain a better view of this delightful valley, which lost none of its beauties from whatever point it was observed. On the opposite side of the mountains which bound Napa Valley on the west, is Sonoma Valley. This is similarly situated, running north and south between ranges of low mountains. It likewise possesses great fertility, but has not the picturesque beauty of Napa. The same may be said of the valleys of Petaluma, Novato, and San Rafael. March 26th. Took an early breakfast and bade adieu to our kind and gentlemanly host, who intended to follow us in a few hours. We did not wait for him, as he wished to stop on the way, and I was desirous to pay my respects to General Hitchcock and the other officers at Benicia before returning to San Francisco. * Obsidian is said by Pliny (Nat. Hist. xxxvi. 26) to have been first found in Ethiopia by a person named Obsidius, from whom it derives its name. It occurs also in various parts of Europe, Asia, and America, and in the vicinity of most volcanoes. Pliny says that gems, and sometimes whole statues, were made of it. He also speaks of four elephants of obsidian, which were dedicated by Augustus in the temple of Concord. As it was quite cool, we were enabled to ride fast and reach Benicia by two o'clock. Took dinner, and afterwards walked out to the military post, when I made my calls upon the officers there. Mr. Osborne joined us at five o'clock, and at seven we took the steamboat for San Francisco, where we arrived at nine. CHAPTER XXIV. THE QUICKSILVER MINES OF NEW ALMADEN. Leave San Francisco-San José Valley-Fertility of the soil-Mission of Santa Clara-San José-New Almaden-Quicksilver mine-Mode of extracting the ore-Large tanks of quicksilver-Account of the quicksilver mines of Spain-Production of this metal in all parts of the world-Situation of the New Almaden mine-Descent into it-How worked-Laborers-Extent of the mine-Effect of the mercury on laborers-History of the mine-Return to San Francisco-Captain Sutter-His history. I REMAINED in San Francisco until the 2d of April, to close up my business there before returning to San Diego. To make the most of my time while in California, I determined to undertake the journey to Monterey by land, first sending forward our outfit and supplies. No event of interest happened while here except a trip which, in company with a small party, we attempted to make in the steamer Active, Capt. Alden, attached to the U. S. Coast Survey, to the Faralones. These are some small rocky islands, which lie twentyfive or thirty miles off the entrance to the Bay of San Francisco. The party, however, were so late in assembling, that after getting outside the entrance or Golden Gate, it was found we could not reach the |