On these metates a flat stone, known as a mano stone, was used, taking the place of the Eastern roller or bell-pestle. It was pushed back and forth with the hand. In the Southwest, California, and Mexico some of the metates are highly ornamented, and have legs, which raised the body of the stone several inches from the ground. When I visited the Chaco Group, in 1897, I saw several hundred metates scattered about on the surface near the ruins. In explorations near Phœnix, Arizona, in November, 1897, to June, 1898, I collected more than ninety good metates. In Kelley Cavern, the Ozark Mountains, which was explored by Dr. Charles Peabody and myself in May, 1908, we found thirty-seven stone mills in one cave alone, and that cavern was no more than two hundred feet across the front and about a hundred feet deep. Mr. J. B. Lewis of Petaluma, California, now deceased, sent me the photograph of a remarkable collection of California mortars. After shipping generous quantities to various scientific institutions in the East, Mr. Lewis still had several hundred in his possession. He constructed an outdoor cabinet of plank and placed thereon a portion of his collection. Fig. 511 illustrates a number of his specimens. It will be observed, by comparison with the figure of Mr. Lewis who is standing at the right of his cabinet, that the largest mortars at the bottom are not upright but are placed at an angle. These mortars range from two feet in diameter to those about a foot high. Many of these weigh as much as seventy-five or a hundred pounds each. The smaller mortars are on the upper rows. Mr. Lewis, during the last two years of his life, wrote me many interesting letters regarding the character of the various stone objects found in his region. He was a keen observer, and during his fifty years of residence at Petaluma he became thoroughly familiar with the various prehistoric sites in that part of California. While I make substantial quotations from these letters, I change his language slightly:— [Illustration: FIG. 510. (S. varying.) Stone bowls from a cache near San Fernando, California. ] [Illustration: FIG. 511. Collection of J. B. Lewis, Petaluma, California. Mr. Lewis, who stands at the right, was fifty years in making this collection. ] “On Sonoma Mountain, seven miles from Petaluma, is a depression in the hills in which the winter rains are collected, forming a large lake or lagoon of two hundred acres, called by the Indians Lagoon La Jara, formerly covered with a tall growth of tules, the home of geese and ducks and blackbirds in their season. Some forty years since, it was drained and brought under cultivation. On ploughing, stones were brought to light called ‘ceremonial sinkers,’ plumbs, etc. As time passes fewer are found, until now only three or four a year.”