97 



falls. Some of the largei- tributai-ies roducetl the lower parts of their 

 courses \vitla sufficient raiiiclitj^ to prevent the cleyelopment of extensive 

 subterranean drainage beneath tiiem, but this was not true of the smaller 

 ones lying on the limestone plain. When the larger streams left the smaller 

 ones hanging high in the air, suliterranean drainage began in earnest. The 



*-;,-^ 



^^ 



IPf****^ - 



>* 



Fig, 16. Welmer Spring, Bloomington WaterworlvS. 



rocks y^ere saturated with ground-water and near the mouths of these 

 streams was under an unbalanced static head of about a hundred feet. 

 This water gradually flowed into the deeper valleys and was in turn re- 

 plenished by more from above, and active underground drainage began 

 find continued fn the manner already indicated. 



-2<;!JS8] 



