1905.] NATURAL SCIENCES OF PHILADELPHIA. 911 



Sixth: That in and around this hole is an enormous quantity of 

 pulverized rock, produced from the strata penetrated by the hole, in a 

 state of subdivision which can be produced by a violent blow, but 

 cannot be produced by forms of natural erosion. 



Seventh : That there can have been no form of natural erosion active 

 in this locality which would have produced this material and have 

 collected it and retained it in the position in which found. 



Eighth: That meteoric material has been found among the filling 

 material of this hole at a depth of 900 feet below the surface of the 

 original plain, and 500 feet below the present bottom of the crater, 

 and 400 feet below the surface of the material which fell back into the 

 crater at the instant of its formation. 



Ninth : That all of the attendant minor phenomena observed can be 

 explained upon the theory of the impact of a great projectile, and none 

 can be satisfactorily explained upon any other theory. 



In view of these positively established facts, the author feels that he 

 is justified, under due reserve as to subsequently developed facts, in 

 announcing that the formation at this locality is due to the impact of 

 a meteor of enormous and hitherto unprecedented size. 



Date of the Occurrence. 



Fortunately there is a means at hand of obtaining a very good idea 

 of the age or rather the extreme recentness of this phenomenon. That 

 is, aside from the evidence of the hole itself and the lack of erosion of 

 the sharp edges of the ejected rocks themselves, and this in a country 

 of desert sand and furious winds, in which all exposed rocks are rounded 

 and sculptured by wind erosion to a marked degree. This evidence 

 comes from a little red sandstone butte some half a mile north of the 

 north edge of the hole. This, as mentioned in the earlier part of this 

 paper, is a portion of what was once the covering rock of this country 

 and which can be seen at a glance to be in process of rapid removal. 

 Now it happens that a jet of the crushed material and broken rock a 

 little more vigorous than most has fallen across this butte, and it can 

 be traced up the near slope and across the top. Then there is an inter- 

 val of fifty feet or so in the lee of the hill upon which none was deposited 

 owing to its horizontal velocity, and then it begins again on the plain 

 beyond for a few hundred feet until it terminates. Now this deposit 

 up the near or southern side of the butte, in spite of the evidently rapid 

 erosion to which it is subject, lies on the surface right up to the cap, 

 without any red sandstone material having fallen or having been 

 washed down upon it. From its appearance it might have been depos- 



