a 
terranean creeks. These in turn were prefoundly influenced by the position 
of the previous Tertiary(?) surface streams. 
In «2 coastal plain the details of the cycle will be scmewhat different, 
but the essential fentures will be similar. The differences will be due to 
the physical characters and structure of the rock, the lack of previously 
establisned drainage lines and the relatively low elevation above sea level. 
Fig. 10. Leonard’s Spring, 8. W. of Bloomington, showing valley with spring 
in distance. 
PIRACY. 
At the time when the subterranean drainage is at the maximum it is 
subject to the same accidents as surface drainage, except that the modus 
operandi is different. Subterranean 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 by another. In each case there are minor varieties of capture such 
as one tributary by another, and self capture. Indeed these are probably 
much more common than the capture of one surface stream by another. 
