104 GLEANINGS FROM NATURE. 



the cavities already formed. Where the slowly flow- 

 ing water has passed through large masses of pure 

 crystalline limestone, the -resulting stalactites and sta- 

 lagmites are often very clear, almost translucent. 

 Where sediment and mud is carried down with the 

 carbonate of lime the resulting formations assume a 

 dirty brown and unattractive appearance. 



Many small caves, and doubtless some large ones, 

 exist in southern Indiana whose presence is, as yet, 

 unknown. In searching for them the bottom of a 

 sink-hole will be the best starting point, the only 

 thing necessary being to blast or dig out the cavity 

 commonly found there, until it becomes large enough 

 to allow a person to enter. 



PORTER'S CAVE. 



The mouth of Porter's Cave is in the north-eastern 

 corner of Owen County, very close to the line between 

 Owen and Morgan counties, and the source of the 

 stream which flows therefrom is distant about one- 

 half mile to the north-eastward. The cave is little 

 more than a narrow, water-worn passage-way through 

 the rocks, which at this point consist of St. Louis and 

 Keokuk limestones, the former comprising the roof 

 and the latter the floor. 



The mouth of this cave is the most beautiful of any 

 visited in the State. It is in the side of a hill at the 

 head of a narrow canyon or gulch, which has been 

 eroded by the stream which flows from the cavern. 

 From the floor of the cave to the bottom of this gulch 

 the distance is 83 feet, down which the stream flows 



