1905.] NATURAL SCIENCES OF PHILADELPHIA. 873 



series has been described in the first part of this paper. We also know 

 that only the uppermost strata have been hurled out of this hole by 

 some terrific force. Briefly, it Tvould seem to me to be impossible that 

 any geologist carefully examining the region could reach the conclusion 

 that this is a volcanic crater, or in any way produced by volcanic 

 agencies. 



II. A steam explosion. This is the theory which seems to have been 

 adopted by the United States Geological Survey to account for this 

 remarkable crater, on the report of one of its members, Mr. Grove Karl 

 Gilbert, and his associates.^ To me it seems incredible that they could 

 have adopted this explanation of the crater and its surrounding phe- 

 nomena, if they had carefully examined the surface as above described, 

 for the following reasons : 



First : Such a violent paroxysmal outbm-st of steam as they assume 

 in order to account for Coon Mountain and its crater is, to the best of my 

 knowledge, unrecorded, unless perhaps in connection with some great 

 volcano, and even there its force, I assume, has been, with few excep- 

 tions, less than the force expended here ; and in such volcanic manifes- 

 tations there were a number of such explosions, not merely one. 



Second: The vast amount of steam required to do the amount of 

 work accomplished at this place could only be stored up in regions of 

 present or recent volcanic activity. There is no evidence that this has 

 ever been such a region. 



Third: As suggested above, it is inconceivable to me that there 

 could have been, even in such a region, much less in a region of undis- 

 turbed stratified rocks, such a single great steam explosion, before 

 which and after which all was quiet. 



Fourth : I assume that such an explosion would not have produced 

 the beautifully round crater which we have here; and, moreover, it 

 seems certain that the country round about would be seamed for miles 

 with cracks and fissures, perhaps more or less radial, through which in 

 aU probability steam would have ascended for many centuries. No- 

 thing of the sort has been found here. It is certain that the crater 

 was made in an instant of time, after which all was as quiet as befo're. 

 Any one visiting the locality is impressed by the many evidences of 

 this fact. It is also certain that the crater is very recent, compara- 

 tively little or no erosion having taken place since it was made. The 

 evidences of this are to be found on every side. If there had been 



"See Thirteenth Ann. Rep. U. S. Geol. Sur., Part I, p. 98, and Fourteenth Ann. 

 Rep. U. S. Geol. Sur., Part I, p. 187. Also Science, N. S., Vol. Ill, p. 1, and 

 Chamberlin and Salisbury's Geology (1904), Vol. I, p. 569. 



