560 PROCEEDINGS OF THE ACADEMY OF [Sept., 



Secondly, vastly more of the fragmentary material, including 

 that which came from its greatest depths, which has been expelled 

 from the crater by the force of the impact, lies on the southern rim 

 than anywhere else. 



Other proofs that the meteoric mass which produced the crater 

 by its impact with the earth approached from this direction are 

 that in the south wall of the crater, composed of great limestone and 

 sandstone cliffs, the fact is clearly discernible that this sandstone 

 and limestone have been lifted vertically some 105 feet out of 

 position for a total length of nearly one-half mile. On either ■ 

 side of this great uplift the formations are tilted violently back- 

 ward, a fault separating them from the central uplifted mass (see 

 Plates XXI and XXII). Moreover, a distinct bending or arch can 

 be seen in the lines of stratification of the rocks composing this 

 central mass which has been vertically uplifted and which probably 

 weighs in the neighborhood of 50,000,000 tons. The highest point 

 of this curvature is in the exact centre or midway between the point 

 where the strata have been turned backward, as described. This 

 would seem to indicate that something was wedged or intruded 

 underneath this great mass of rock and lifted it vertically upward. 

 The central portion of this mass of rock so uplifted is almost due 

 south of the centre of the crater or nearly opposite to that portion of 

 the crater's rim and the plain beyond on which the greatest number 

 of ordinary Canyon Diablo meteorites and the so-called "shale 

 ball" meteorites have been found. Also beginning at the north the 

 strata exposed in the circular wall of the crater increase in the dip 

 representing their backward tilting on each side of the crater right 

 around to the faults which mark the east and west sides of this up- 

 lifted mass (see Plates XXI and XXII) . When these facts are consid- 

 ered in connection with that of the great fragmentary masses of lime- 

 stone being collected together in what I have heretofore referred to 

 as "fields of limestone boulders," which lie to the east and west of a 

 north and south line passing through the crater, conviction is forced 

 upon the mind that the mass which made the crater, and which 

 according to our present knowledge of physics and chemistry must 

 lie somewhere in its depths, approached the earth from a northerly 

 direction and held to its course as a rifle bullet woXild until perhaps 

 it came to the top of the hard Red Beds sandstone stratum, when 

 possibly it may have been deflected somewhat. Apparently, how- 

 ever, it advanced sufficiently far underneath the white or gray 

 sandstone and th(^ overlying limestone to uplift the portion of the 



