556 PROCEEDINGS OF THE ACADEMY OF [Sept. 



FURTHER NOTES ON METEOR CRATER, ARIZONA. 

 BY DANIEL MOREAU BARRINGER. 



I present this as a supplement to my paper, entitled "Coon 

 Mountain and Its Crater," published in the Proceedings of The 

 Academy of Natural Sciences of Philadelphia in December, 1905, 

 and to my more comprehensive and necessarily more accurate paper 

 (owing to the amount of exploration work Avhich has been done), 

 read before the National Academy of Sciences at its autumn meeting 

 at Princeton University, November 16, 1909, with a few additional 

 and apparently conclusive arguments with regard to the correctness 

 of the impact theory of origin of what is now known as the Meteor 

 Crater of Arizona. 



One of the most significant minor facts in connection with this 

 remarkable crater is the discovery by those who have conducted the 

 extensive exploratory work there of quite large quantities of quartz 

 glass, which is undoubtedly fused sandstone and has been so de- 

 scribed by Merrill.^ An examination of the specimens now on 

 exhibition at the American Museum of Natural History, New York, 

 will immediately convince the most skeptical that this is nothing 

 but fused sandstone. 



It does not appear that those who have written on the interesting- 

 subject of the origin of this crater in Arizona, myself included, have 

 used this fact, and the circumstance that the material is abundantly 

 stained with nickel-iron oxide, as a conclusive argument — for such it 

 is — in favor of the impact theory rather than the volcanic theory of 

 origin. I am assured by Dr. Merrill and others that there is no 

 record of a sudden outburst of volcanic action wherein the heat 

 generated was sufficient to fuse crystalline quartz. The only case 

 of quartz being fused by a sudden rise in temperature to the necessary 

 degree of heat to effect a result comparable to that produced here 

 is that of the more or less familiar action of the lightning striking 

 sandstone or sand and altering it to what is known as fulgurite 

 glass. No volcanic action, however violent or however long con- 



' Proc. U. S. National Museum, Vol. XXXII, pp. 547-5.50, June 15, 1907, 

 and Snii.lli.sonian Misc. CoUcrlinns (Quartprly Issuo), Vol. .50, Part 4, pp. 4(11- 

 498, pis. 61-75, January 27, 1908. See also the description of this inetanioi- 

 phosed sandstone in my National Academy paper. 



