44 KINDLE 



The small surface stream which flows through the caved valley 

 and very near the "cave-in" which was first to develop has been 

 suspected of being the cause of the trouble by some of the local 

 students of the problem. The hypothetical manner in which the 

 stream may be supposed to have accomplished the caving was by 

 partial discharge of its water through some originally small adventi- 

 tious outlet into the portion of the limestone cavern under Baldwin 

 street. This flow, gradually increasing from a slight seepage at 

 first to a discharge sufficient to have considerable erosive power on 

 the marl, gradually undermined the street till the collapse resulted. 

 The result of this first " cave-in," which may be considered to com- 

 prise the nearly adjacent holes Nos. i and 2 (PI. I) was to block or 

 dam the subterranean stream till it rose to the level of the marl and 

 clay beds above the limestone. The water thus dammed may be 

 supposed to have softened the superficial beds brought in contact 

 with it and have lead to the successive development of holes Nos. 

 3 and 4. The numbering of these holes on the map (PL I) cor- 

 responds to the order in which they developed. This hypothesis 

 calls for a stream in the cavern flowing northeast. We are without 

 definite information regarding the direction or the movement of 

 water in the cavern, a current guage having failed to register any 

 current. If this explanation of the caving were correct, careful 

 examination of the artificial conduit of the stream in the vicinity 

 of the caving should indicate the supposed diversion of water. A 

 close examination of the conduit for this purpose by the city engi- 

 neer, however, failed to show any such divergence. This hypothe- 

 sis, therefore, appears to be supported by no ascertained facts, and 

 it affords no explanation of the very suggestive sequence of 

 events represented by the beginning of caving shortly after the 

 starting of a high power pump nearby. 



Another theory of the cause of the caving which requires consider- 

 ation has been proposed by Hon. J. Yost. The well at the Smith 

 ice-plant which is located about 150 feet from the line of caving, 

 according to this theory, served to connect the strong stream near 

 the bottom of the 8oo-foot well with the cavern under the " cave- 

 ins" which previously had been empty or only partially filled with 

 water. During the month which passed between the completion 

 of the well and the installation of the i co-gal Ion pump, this cavern 



