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Rh with the petrified trunks of giant trees, at intervals for several miles. This locality is now the subject of much curious investigation, and the origin of the "Petrified Forest of Calistoga" has been speculated upon learnedly by many scientists. The wood retains its grain perfectly, no difficulty being found in counting the consecutive rings supposed to indicate the years of growth of each fallen giant of the forest. The color is a whitey-brown, and there are occasional layers of clear white quartz in small crystals, apparently the result of water deposits. Evidences of remote volcanic action abound in the vicinity, the whole surface of the ground being composed, in fact, of tufa, ashes, and coarse, broken sandstone, mixed with metamorphic rock, ascribed to the cretaceous age, and indicating disturbance by severe earthquakes or volcanic convulsions of a comparatively recent date. None of the trees are perfect—only the trunks and main roots appearing to have been petrified—and all are lying flat upon the ground, or half buried in it, scattered and broken, as if blown down by a sudden gale or whirlwind. Some of the trunks are from fifty to seventy-five feet in length, and nearly perfect, and others mere stumps and fragments, from ten to thirty feet long. Tourists visit the locality almost daily, and sample the trees so freely that a few years will suffice to obliterate all traces of the now famous grove. The stone takes a fine polish, and is much prized for seal-rings and jewelry.

Professor Marsh, of Yale College, who examined the petrifaction, on the ground, in 1870, came to the