FORMATION OF THE CAVE. 



deep, covering an area of from five acres to two thousand. The 

 rim of sandstone surrounding these depressions is, generally, 

 nearly level ; the outcropping rocks within are also nearly horizon- 

 tal. Near the centre there is an opening of from three to fifteen 

 feet in diameter ; into this opening the water which has fallen within 

 the margin of the basin has been drained since the day when the 

 rocks exposed within were raised above the drainage of the coun- 

 try, and thus, by the slow process of washing and weathering, the 

 rocks, which once filled these cavities, have been worn and carried 

 down into the subterranean drainage of the country. All this has 

 evidently come to pass in the most quiet and regular manner. 

 The size of the central opening is too small to admit extraordinary 

 floods ; nor is it possible, with the level margin around, to suppose 

 that these cavities were worn by eddies in a current that swept the 

 whole cavernous member of the subcarboniferous limestone of 

 western Kentucky ; but the opinion is probable that the upheaving 

 force which raised these beds to their present level, at the same 

 time ruptured and cracked the beds in certain lines ; that after- 

 wards the rains were swallowed into openings on these fractures, 

 producing, by denudation, the basins of the sinkhole country, and 

 further enlarging the original fractures by flowing through them, 

 and thus forming a vast system of caverns, which surrounds the 

 western coal field. The Mammoth Cave is, at present, the best 

 known, and, therefore, the most remarkable." 



So much has been written on the cave and its wonders, that to 

 give a description of its interior would be superfluous in this 

 connection, even could we do so without unintentionally giving 

 too exaggerated statements which seems to be the natural result 

 of a day underground, at least so far as this cave is concerned, 

 for after reading any account of the cave, one is disappointed at 

 finding the reality so unlike the picture. As the Association party 

 was accompanied by one* who, while a most enthusiastic collector 

 and explorer, was also a calm recorder of statements made by 

 the geologists of the party, we cannot do better in conveying to 

 our readers the general geological character and structure of the 

 cave than to copy his account. 



" As we expected to remain within the cave a long time, our 

 trusty guide, Frank, had provided himself with a well-filled can 

 of oil, to replenish our lamps, and with this strapped upon his 

 back he led the way into the thick darkness. We shall attempt 

 no description of the cave. Its darkness must be felt to be ap- 

 preciated, and no form of expression, understood by mortals who 

 have never descended to its cavernous depths, nor trod its gloomy 



* W. P. FJSHBA.CK, Esq., of the Indianapolis Daily Journal. 



