320 ANTSrtJAL REPORT SMITHSONIAN INSTITUTION, 1950 



The Nullagine sediments examined to the north of the crater are gently 

 folded and faulted on a small scale. It seems reasonable to postulate 

 that the general outward dip of the beds forming the wall of the crater 

 is due almost entirely to movement resulting from the explosion of 

 the meteor. 



Similar structure has been established in the cases of the Meteor 

 crater of Coconino County, Ariz. (Barringer, 1909), and Texas crater 

 in Ector County, Tex. ( Barringer, 1909 ) . It is likely that the bending 

 described from the north wall of the crater is at least partly a structure 

 of premeteor age, as it would appear impossible for surface beds of 

 hard quartzite to bend in such a way without considerably more 

 fracturing. 



An examination of the crater both on the ground and from aerial 

 photographs (pi. 2) gives the impression that a greater volume of 

 fractured rock has been piled around the southwest portion of the 

 crater than around other portions, suggesting that the meteor was 

 moving in an arc from the northeast toward the southwest when it 

 struck the ground. 



From a study of craters on the earth's surface and on the moon, 

 Dietz (1946) and others have suggested that the radial symmetry and 

 circularity of craters such as the Meteor crater and those on the moon's 

 surface are due to exploding meteors. Explosion craters, in contrast 

 to percussion craters, have circular shape and well-developed radial 

 symmetry regardless of the angle of incidence (fig. 3). 



No silica glass or sintered rock has been discovered in the area, but 

 there is every probability that further work will disclose the presence 

 of material of this character. 



Table 1. — Analysis 



Nickel, Ni in metallic portion. 



Nickel, Ni total 



Specific gravity 



Fragments of various size of heavy metallic material were found 

 around the rim of the crater, particularly along the southern sector. 

 E. O. Chalmers, curator of minerals of the Australian Museum, has 

 advised that "the specimen contains 1.9 percent of NiO, which is far 

 in excess of what would be expected in terrestrial rock." 



Samples of meteoritic iron were submitted to the Western Australian 

 Government Chemical Laboratories. The following information is 

 taken from their report. The samples consisted of two fragments, 



