91 



terraiiean ci'eeks. These in turn were in'ofoniiclly iiirluenced by the positi'ni 

 of the pvevions Tevtiaryi ?) miiriV.ee f;treams. 



In a coastal ])lam the details of tlie cycle will be somewhat ditf event, 

 but the essential features wiil lie similar. The differences will be due to 

 the physical characters and struct are of the rock, the lack of previously 

 established drainase lines and tlie I'clritive'.y low elevation aliove sea level. 



Fig. 10. Leonard's Spring', S. W. of Bloominglon, showing valley witli sprint;' 

 in di-stance. 



PIKx\.cr. 

 At the time when the subterranean draina^Lce is at the maxinunu it is 

 subject to the same accidents as surf;\ce draimige, except that the modus 

 operandi is different. vSubterranean piracy falls under two distinct heads, 

 the capture of one surface stream by another through subterranean drain- 

 age, the easiest form to observe, and the capture of one subterranean 

 stream bj' another. In each case there are minor varieties of capture such 

 as one tributary l)y another, and self capture. Indeed these are probably 

 mncli more common than the capture of one sui'faee stream Ijy another. 



