494 H. L. FAIRCHILD ORIGIN OF METEOR CRATER, ARIZONA 



Up to the present time more tlian 50 pits and trenches have been exca- 

 vated in tlie debris of tlie outer slopes ; seven shafts ha-^e been dug in the 

 floor of the crater, three of them to the depth of 200 feet or over; and 

 eight drill holes have been sunk in the central part of the crater, four of 

 which passed entirely through the white sandstone and penetrated the 

 underlying dark red sandstone at a depth of 880 feet below the crater 

 floor, to a total depth of over 1,050 feet. 



These explorations have developed a mass of new and important facts 

 which favor the theory of meteoric impact origin, and certainly rule out 

 the hypothesis of igneous or volcanic origin. The writer visited the 

 crater during the past summer and studied the phenomena under the 

 guidance of Mr S. J. Holsinger, one of the mining company, who has 

 been camping on the crater rim for four years and directing the explora- 

 tion. 



Professor Branner liad visited the crater a few weeks earlier, and tlie 

 writer agrees with him that if the phenomena are not of meteoric origin 

 then they constitute the most interesting geological puzzle of the present 

 time. 



To Messrs Barringer, Tilghman, and Holsinger the writer is under 

 obligation for courteous assistance. Their two papers, noted above, 

 contain an array of interesting facts relating to the crater phenomena. 

 The purpose of this writing is' to bring before the Geological Society the 

 more salient and important facts. 



The Eock Strata 



The rocks belong in the Grand Canyon series. The outcrops in the 

 crater and the deep drilling give the following section : 



1. Eed sandstone, thickness 30 to 40 feet. 



2. Aubrey limestone, yellowish, 250 ± feet. 



Sci., vol. 49, February, 1905, pp. 101-110. Other writers on the irons are Brezina, 

 Cohen, and Huntington. 



The stony meteorite referred to by Mr Barringer (p. S83 of his paper) was described 

 by J. W. Mallet, in Amer. .Jour, of Sci., vol. 21, May, 1906, pp. .347-35.5.- 



Dr .1. C. Branner presented the papers of Messrs Barringer and Tilghman before Sec- 

 tion E, American Association for the Advancement of Science, at the Ithaca meeting, 

 June 29, 1906, with the results of his own study of the phenomena, which favored the 

 view of meteoric origin of the crater. This is reported in Science, vol. 24, September 21, 

 1906, pp. 370-371. 



At the 10th Session of the International Geological Congress, in Mexico, September 14, 

 1906, H. L. Fairchild presented the new facts favoring the impact origin of the crater, 

 and exhibited the various materials. The record will be found in Compte Rendu, X 

 Session, Congres Geol. Inter., Mexico, 1906. 



O. C. Farrington has analyzed the siderite oxides ("iron shales"), and discussed their 

 origin and relation to the typical Canyon Diab?o irons, in Amer. Jour, of Sci., vol. 22, 

 October, 1906, pp. 303-309. 



