METEOR CRATER OF ABIZOXA. 323- 



(4) Sand and rock, sand grains cinished slightly, if reet. 



any, and not metamorphosed, barren of meteoric 

 material 220-52O. 



(5) Sand and '' silica" (rock-ilom-), with abundant 



slag-like material containing iron and nickel, 



and metamorphosed sandstone ... ... ... 520-600 



(6) Fine silica powder (rock-flour) and sand, no 



meteoric material ... ... ... ... 600-620 



(7) Bed-rock, a grayish sandstone rapidly becoming 



yellow and harder, not metamorphosed ... 620-720 



The material mentioned under 3 and 5, as reacting for nickel, 

 C(.ntained nothing that could be identified beyond question as of 

 meteoric nature. There were occasional minute magnetic particles 

 which gave a reaction for nickel and phosphorus, and greenish sili- 

 ceous particles resembling, under the microscope, furnace slag. There 

 would seem to be no doubt as to its meteoric nature; but, as stated, 

 this could not be absolutely proven. In all cases the drill passed 

 through a variable thickness of the material called '"' rock-flour," of 

 the same nature as that found outside on the crater rim, and which 

 the" microscope and chemical tests showed to consist of almost pure 

 silica and derived from the gray sandstone. This material, it is 

 important to note, was not the result of a simple mechanical dis- 

 integration of the sandstone, but every granule had been shattered 

 as though by a sharp, sudden blow from a hammer, or perhaps a 

 shock such as might be imported by a blast of dynamite. As above 

 noted, the drilling was stopped in nearly eveiy case when firm rock 

 Avas reached. The seven cores examined came from varjdng depths 

 below the bottom of the crater up to 1,080 ft. They were in all cases 

 of a brown-red sandstone, firm, intact, and wholly unchanged by any 

 of the forces that had operated on the overlying materials. 



Summing up then this all too brief resume of the subject, it 

 appears that if the results of these borings are to be considered as 

 .final, the phenomena of the crater are wholly superficial and limited 

 to the limestone and gray sandstone; that both of these rocks have 

 been shattered as by a mighty blow from extraneous sources, and 

 their material scattered, about over the surrounding plain ; that 

 incidentally, a portion of the quartz sand has been fused, and con- 

 verted into a silica pumiceous form and a portion actually rendered 

 crystalline, this variety occurring in masses with a secondary, platy 

 structure not conformable with the original bedding. No meteoric 

 material has been brought to light by the borings other than noted, 

 nor in quantities sufficient to suggest a body of such size as could 

 have produced the crater. If it were thus produced, we are forced to 

 the conclusion that the mass was practically all dissipated through 

 the heat of impact and the subsequent weathering. It is felt that 

 there is no doubt but that the meteoric irons — the shale-ball irons 

 found in the crater-rim — were thrown out together with the debris 

 from the interior. Whether or not this indicates a steam explosion 

 subsequent to the problematic impact, cannot be considered as settled. 

 For a discussion of this part of the subject I have to refer to my 

 original paper, as well as to a discussion of the relation of these 

 buried fonns to the iron masses found scattered over the surface of 

 the plain. 



