1905.] NATURAL SCIENCES OF PHILADELPHIA. 877 



to it in their report. It is certainly different from any substance in 

 nature with which I am famihar, and had they taken the trouble to 

 have it analyzed they would have found that the large pieces almost 

 invariably contain nickel (certainly in all the specimens examined) 

 to the same extent, proportionately speaking, as it is found in the 

 Canon Diablo meteoric iron, from which this magnetic iron oxide was 

 no doubt produced. However, if they had merely broken open some 

 of the larger pieces of this magnetic iron oxide, which it seems to me 

 they could not have failed to see, they would have observed in some 

 of the specimens the characteristic green hydroxide of nickel. The 

 iron oxide was produced, as I assume, by the heat generated from 

 friction while the great iron meteor passed through the earth's 

 atmosphere. As above stated, it has been determined for us that 

 the larger pieces of this so-called "iron shale" contain invariably 

 iron, nickel, iridium and platinum in the same relative proportion 

 (remembering that two are in the form of oxide while the others are 

 in the metallic state) as they are found in the iron from which this 

 material was separated. In the very minute pieces of shale the nickel 

 has been leached out to a greater or less extent. For the sake of clear- 

 ness and because of the peculiar laminated structure, I shall hereafter 

 refer to this magnetic oxide of iron as "iron shale," adopting the local 

 name by which it is known. This iron shale is very much more mag- 

 netic than the original metallic meteoric iron, which in some speci 

 mens is only feebly so. 



It should be stated in this connection that the surface of the sur- 

 rounding country for perhaps several miles, concentrically around the 

 crater, contains minute particles of this iron shale, either in the shape 

 of fragments or as spherules. It is found everywhere in the vicinity 

 of the crater, on the rim and on the outside plain. We have assumed 

 that these small particles once constituted a portion of the great lumin- 

 ous tail of the meteoric body which, in our belief, by its collision with 

 the earth made the crater. 



Having observed all these things, containing as they do many argu- 

 ments in favor of the theory that this great hole in the plain was pro- 

 duced by the impact of a body falling out of space, and against the 

 theory that it was produced by either volcanic action or by a steam 

 explosion, it naturally suggested itself to us to endeavor to prove 

 absolute synchronism of the two events, namely, the falling of a very 

 great meteor on this particular spot and the formation of this crater. 

 The easiest method of doing this, which at once suggested itself to us, 

 was to have a number of open cuts made through the silica and rock 



