388 WILL SCOTT. 



lower one is the outlet and is known as Shawnee Cave. The 

 four other openings have been formed by the collapse of two 

 sections of the roof and are known as, Lower Twin Cave, Upper 

 Twin Cave, Lower Dalton Cave, and Upper Dalton Cave, re- 

 spectively (see map). 



Vertically the cave is located in the Mitchell limestone, and has 

 been formed by solution along seams in the rock. These seams 

 follow approximately cardinal directions and hence cross at right 

 angles. The result of this is that much of the cave consists of 

 straight passages at right angles to each other. The erosive 

 action of the stream being much greater in the eddies at the turns 

 than in the straight passages deep pools are formed at these 

 points. 4 



Obstructions. The cave stream has been obstructed more or 

 less completely at four points in the region that I have explored. 

 The upper obstruction has been formed by the collapse of the 

 roof, possibly below a sink-hole, between the Dalton caves (136, 

 37). 1 The second in a similar manner between the Twin caves 

 (132, 33). A large part of the upper dam has been removed 

 by solution and erosion, so that the stream flows over it. 



At the Twin caves the obstruction is complete at ordinary 

 stages of the stream. It occurs at a right-angled turn in the 

 cave. A new passage is being formed cutting off the obstructed 

 corner. The lower end of this new passage is a few feet below 

 Lower Twin Cave, the location of its upper end is not yet posi- 

 tively determined. The passage is too small to be explored and 

 insufficient to accommodate the stream in times of flood ; in such 

 times, the water flows over the obstruction between the two caves 

 and resumes its original course. 



The third obstruction is 1,400 feet below Lower Twin Cave 

 at the so-called "Big Room" (I-I5, 20). Here a number of 

 old caves crossed the present stream at a higher level. The 

 strata between these two cave levels fell and for a time completely 

 dammed the stream. Deposits of gravel and clay were then 

 formed above this point. In the side passages that are protected 

 from erosion by the cave stream, the deposits still reach the roof. 

 Much of the obstruction and resulting deposits have been removed 

 by the cave stream. 



1 Numbers refer to map. 



