GEOLOGY OF THE NEW YORK CITY AQUEDUCT 79 



the escarpment is reached. It was further beheved that the cov- 

 ered portion is wholly drift-filled down to the Onondaga. It was 

 easy therefore to estimate the approximate profile and suggest the 

 point of greatest probable depth. The accompanying figure illus- 

 trates the form and structure of this valley. Each valley has had 

 in a smaller way a similar study and adjustment of location of line. 

 The final result is shown on the accompanying map which indi- 

 cates the course of the aqueduct as now being constn,icted. 



