564 PROCEEDINGS OF THE ACADEMY OF [Sept., 



explosion should have produced not only such a peculiarly sym- 

 metrical crater as has been described in the various papers whicli 

 have been recently written concerning it, but should have produced 

 one which furnishes so much other evidence strongly confirming 

 the theory of impact as against the theory of steam explosion. 



Consequently, it is perfectly fair mathematically to multiply these 

 three and for one to say, on the theory of probabilities, that the 

 chances are one in the product of all these millions that the crater 

 was formed by a steam explosion. This of course is negligible. 



Explanation of Plates XXI-XXIII. 



Plate XXI. — Map of Meteor Crater, Arizona (six miles south of Sunshine 

 Station, Atchison, Topeka & Santa Fe R. R., Coconino County, and in 

 Sections 13 and 24, T. 19, N. R., 12| E.). 



Plate XXII. — Rough sketch map showing distribution of major portion of 

 fragmentary material ejected from Meteor Crater, Arizona. 



Some rock fragments have been thrown as far as two miles from the 

 crater. This map merely shows manner of distribution and relative 

 quantity of material near the crater. Very much more material has 

 been thrown to the south (generally speaking) than elsewhere, i.e., the 

 mass of rock fragments is much thicker there than elsewhere and the 

 rock has been more finely crushed. The rock fragments seem to have 

 been thrown furthest to the northeast by east, where they thinly cover 

 a large area. 



Legend. — 



»■'-" Crater Rim. 



Lower limit of }>tdk. of ejected material which forms to a large extent 

 the so-called mountain. This line necessarily approximate. 



Limestone fragments, the most coherent rock thrown out of the crater. 



am Fields of big limestone boulders on the east and west slopes of the 

 mountain. 



!^ White or gray saccharoidal sandstone fragments. These frequently 



show cross bedding. 

 ^^ Brown sandstone fragments and brown sand due to their disintegration. 



Much of this sand has been drifted to the eastward by the prevailing winds. 



P^l Thin sheets or individual masses of ejected limestone far out on the 

 plain. These scattered fragments are found H miles from the crater 

 rim to northeast, If to 2 miles east and about 1 mile southeast. Map 

 too small to show their distribution except in a general way. 



Plate XXIII. — -Map showing distribution of meteoric material around Meteor 

 Crater, Coconino County, Arizona. 



Legend. — 



® Meteoric irons (ordinary Canyon Diablo sideritcs) from 10 pounds to 



547 pounds, discovered by Standard Iron C()m|)any. 

 ^>- Meteoric- irons, from 10 pounds to 1000 pounds, discovered by Mexicans 

 employed by F. A. Volz ct al. previous to acquisition of i)roperty by S. I. Co. 

 ■•■ Meteoric irons. Small. Discovered by S. I. Co. Thousands of the small 

 irons found. Hence (listril)ut ion only approximated. (These are generally 

 only a few grains or ounces in weight, irons weighing from 1 to 10 pounds 

 found only occasionally.) 



