THE ORIGIN OF THE CAVES AT PUT-IN-BAY, OHIO. 



Kenneth Cottingham. 



Certain features of the caves on Put-In-Bay Island are so 

 unusual and so different from the ordinary solution cavern as 

 to be apparent to the most casual observer. The absence of 

 rounded forms, the sub-angular appearance of floor and roof, 

 the similarity between depressions in the floor and pro- 

 tuberances on the roof, or vice-versa, impress even the tourist. 

 The caves at Greenfield, Ohio,- occur in rock of almost identical 

 lithology — in fact, in the same formation though in a different 

 member. Yet the Greenfield Caves consist of narrow, winding 

 passages, often on two or three separate levels — the true type 

 of caves produced by solution. At Put-In-Bay the rooms are 

 ■cavernous — low, nearly as broad as long, and without passages. 

 It is true that if the Put-In-Bay Caves were formed entirely by 

 solution — and presuming that they are recent — just such 

 cavernous features would result, for the ground water would 

 stand at lake level and be comparatively quiet; while at Green- 

 field the ground water was well above local stream level, and 

 therefore more potent. Yet this offers only a partial explana- 

 tion and accounts for nothing beyond the general form of the 

 caves. 



One of the first to advance the anhydrite-gypsum theory for 

 the origin of the Put-In-Bay Caves was E. H. Kraus (Am. Geol. 

 XXXV, 167-71). While no trace of either anhydrite or gypsum 

 was found in the caves, Kraus cites the occurrence of the latter 

 in wells, surrounded by highly brecciated dolomite. The 

 theory that the swelling of hydrated anhydrite could be great 

 enough — either in volume or intensity — to produce caverns 

 at first seems untenable. The conversion of anhydrite to 

 gypsum is accompanied by a change in volume variously 

 estimated. Credner, Fritsch, Bauer and Geikie hold the 

 increase as low as 33%. By Nauman, Zirkel and Dana it is 

 placed at 60%, and J. Roth has calculated it to be as high as 

 '62%. Kraus points out that the increase of volume of water 

 converted to ice is 9% to 10%, while the resultant force exerted 



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