PHYSICAL NOTES ON METEOR CRATER, ARIZONA. 



By WILLIAM FRANCIS MAGIE. 



(Read April 22, 1910.) 



I. Aleteor Crater is situated near the center of the northern half 

 of Arizona, six miles south of the line of the Santa Fe Road, about 

 thirty miles east of Flagstaff. It is an immense hole or crater-like 

 excavation in the otherwise level plain, nearly circular in shape, about 

 4,000 ft. across at the top, and surrounded by a rim of elevated 

 strata and ejected material. This rim is from 120 ft. to 150 ft. 

 high, and the floor of the crater is 570 ft. below its edge. From the 

 edge there slopes down a very steep inclined talus, ending in the 

 level floor. 



The ejected material is mostly composed of broken and irregular 

 limestone boulders from the higher stratum, some sandstone boulders 

 from the next stratum, and an immense quantity of sandstone, which 

 has been pulverized so that each grain of it has been broken into 

 fragments so small that most of them will pass through a 200-mesh. 

 The borings that have been made by the Standard Iron Company 

 have shown that the interior of the crater is filled to a depth of 600 

 ft. or more with similar fragments of rock and with this pulverized 

 sandstone. 



The crater is the center of the area in which the Canyon Diablo 

 meteorites have been found. These are of iron, carrying about 6 to 

 8 per cent, of nickel, and about three quarters of an ounce of 

 platinum and iridium to the ton. They also contain microscopic 

 diamonds, in large numbers, so that it is a work of great labor and 

 difficulty to cut out a specimen for testing. Another variety of iron 

 is also present, and judging from the residue of iron oxide which it 

 has left, was originally present in much larger quantities than the 

 Canyon Diablo iron. This differs from the Canyon Diablo iron in 

 containing chlorine. It generally is found in oval or globular masses. 

 It oxidizes readily, and forms sheets or plates of iron oxide, re- 



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