106 





Fig'. 24. Abandonod chanuol of Lost river mpntiunod in explanation of pre- 

 vious figure. 



Fig. io. I'liautom lalie, near Toyali. Texas. A collapse sink where the suli- 

 terranean stream is revealed. The roof, of Washita limestone, collapsed, tilling the 

 channel and forcing the stream to the surface — cave on the left — in a stream about 

 six feet In diameter. It fills the depression formerly occupied by the roof with 

 water and enters sinks in the immediate foreground to its channel below. 



