Studies of Some American Meteorites

Abstract

THE large crater, three-quarters of a mile across and 500. feet in depth, near Canyon Diablo, in Arizona, which it is supposed was produced by the impact of an enormous meteorite, has already been described at some length in NATURE (1906, vol. Ixxiv., p. 490). Since that date the locality has been visited by Dr. George P. Merrill, of the United States National Museum, and in a paper published in the Smithsonian Miscellaneous Collections (1908, vol. 1, pp. 461-90, with fifteen plates) he gives the results of his observations, and reviews the evidence for and against the meteoric hypothesis. In the hope of finding a large mags of metallic nickel-iron, Messrs. D. M. Barringer and B. C. Tilghman have made a detailed examination of the crater, and have put down a number of bore-holes to the depth of noo feet in its floor. Beneath the surface debris from the sides of the crater there is a thick bed of lake deposits; this lies on a crushed and pulverised sandstone containing fused and pumiceous fragments and particles of nickel-iron, while at a depth of about 600 feet the undisturbed red sandstone of the district was met with. No large mass of meteoric iron was encountered; and with the exception of four small pieces, the numerous masses of Canyon Diablo meteoric iron have all been found outside the crater. All the evidence undoubtedly points to the crater having been formed by the impact of a meteorite.