Ch. 7: Quartz Group - Opal, Rock Crystals, Amethysts, Rose Quartz, Agate, etc.

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	UNITED STATES, CANADA AND MEXICO 131 Blake mentions the occurrence of large masses of white chalcedony, delicately veined and in mammillary sheets, near the Panoche, in Fresno County and in Monterey County, Cal.; on Walker River, Nev. ; of a fine pink color near Aurora, Esmeralda County, Nev.; and in pear-shaped nodules in the eruptive rocks between Williamson's Park and Johnson's River, Los Angeles County, Cal. A very interesting form of chalcedony is found in the vicinity of Crawford, Darres County, Neb., where nearly all the narrow cavities in the large fossil bones found are entirely filled with cores of gray chalcedony, which are left scattered in great numbers over the ground when the bones are broken or have become weathered. It also fills all the seams in this formation, which after weathering leaves walls of chalcedony, varying in thickness from a few inches to that of paper, projecting from the ground often to the height of several feet, and sometimes extending across the country for miles. At Washougal, Wash., there has been found quite a variety of fine agates and moss agates in the form of pebbles from i to 4 inches in diameter. The corals and sponges of Tampa Bay, Fla., which are so often altered to chalcedony by the silicious waters, are at times filled with a fluid which was imprisoned while the regular deposition of the silica was closing the apertures that admitted the water. They are always lined with drusy quartz, as are those found in Uraguay, the so-called hydrolites, orwater-stones, and, if not as beautiful as the latter, they are even more interesting, and have been sold from $2 to $20 each. Beautiful pebbles of agate and chalcedony are found in abundance along the beach of Crescent City, Cal., and are often cut as souvenirs. They are usually of a light color, but delicately veined and marked. Beautiful little agates from Pescadero Beach in California are sold in large quantities, and in different forms, polished and unpolished, loose or in vials of water. Occasionally some of these are found enclosing, like the hydrolites from Uraguay and the chalcedony from Tampa Bay, Fla., a pebble moving in liquid. These pebbles, which may well be called sealed flasks, vary from 1/10 to 1/4 inch, and rarely are 1 inch in diameter. They are also found at Yaquina Bay, Ore. In the pebbly drift of the Colorado River the agates are more highly colored, more abun-

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