MERRILL] METEOR CRATER OF CANYON DIABLO, ARIZONA 463 



give the Aubrey limestone at Canyon Diablo as probably not far 

 from 300 feet in thickness, the gray sandstone 400 to 500 feet 

 in thickness, and the still lower yellow-red sandstone about 1,000 

 feet in thickness. 1 The residual overlying red sandstone in the 

 mesas is rarely over 15 to 20 feet in thickness, never, according to 

 Mr. Barringer, over 50 feet. These beds all lie approximately 

 horizontally, and almost as little disturbed by orographic movements 

 and other dynamic agencies than those of erosion as when first laid 

 down. The country is arid, the average annual rainfall being but 

 8 inches. The dryness of the soil consequent upon this slight pre- 

 cipitation is increased by numerous deep canyons and even earth 

 cracks, 2 which quickly drain off all surface water. The country is 

 essentially a desert, though affording at certain seasons of the year 

 good pasturage for numerous flocks of sheep. Viewed from a slight 

 elevation, and particularly when the sun is approaching the horizon, 

 these great stretches of gray plain, with their scanty vegetation 

 and occasional streaks of red from the residual sandstone mesas, 

 are fascinating in the extreme and well merit the descriptive name 

 of "Painted Desert," as applied by the early explorers of the region 

 to the northwest, of which they are but a continuation. 



III. The Crater 



Historical References. — The occurrence of a peculiar crater-form 

 depression within an elevated rim of limestone and sandstone, some 5 

 miles south of the railroad and 12 miles southeast of Canyon Diablo, 

 has been known for several years, but was first brought prominently 

 before the scientific world by A. E. Foote 3 in 1891, and through the 

 later writings of G. K. Gilbert, 4 D. M, Barringer, B. C. Tilghman, 5 

 and others. 



This crater, through a singularly inappropriate use of terms, has 

 become known in the literature as Coon Mountain, or Coon Butte, 

 although occurring in a region where raccoons are rarely known 



1 The record at Winona, where the limestone had been very considerably 

 eroded, was: Aubrey limestone, 185 feet; light gray sandstone, 456 feet; red 

 sandstone, 16 + feet. (Darton.) 



2 The Canyon Diablo, the Canyon of the Little Colorado, the Grand Canyon 

 of the Colorado, and the earthquake cracks described by Gilbert (Science, vol. 

 ir, 1895, p. 117) are sufficient examples of these. 



3 American Journal of Science, vol. xi.n, 1891. p. 413. 



4 Presidential Address, Geol. Soc. of Washington, 1896; also Science, vol. 

 in, 1896, p. 1. 



6 Coon Mountain and Its Crater, Proc. Acad. Natural Sciences, March, 1906, 

 p. 861. 



