﻿yb NEW YORK STATE MUSEUM 



buried channels beneath the drift, (b) the character and depth of 

 the drift, (c) the kind of bed rock, (d) the condition of bed rock 

 for construction and permanence of tunnel, (<?) the underground 

 water circulation, (/) the occurrence of folds and faults, (g) the 

 position of weak zones, (h) the depth required for substantial con- 

 ditions, and many other similar problems. 



These need not be treated in their original form. Indeed many 

 of them have now ceased to be problems in any real sense, for sub- 

 sequent provings have made them simple facts, and wholly new 

 questions came to take their places. In some of the larger prob- 

 lems, however, it is believed that a treatment which involves a dis- 

 cussion of the original problem and the method of solving it, to- 

 gether with the data thus secured and the final interpretation of 

 geologic features as now understood or established will be more 

 instructive than a mere enumeration of the collected results. 



So far as possible each problem is treated as a unit and fully 

 enough to be understood by itself. But a general knowledge of 

 local geology as outlined in part I is assumed. 



