20 NEW YORK STATE MUSEUM 



Other problems 



The foregoing observations apply likewise to the other larger 

 problems of the aqueduct line. A list of the larger ones requiring 

 extensive exploration and illustrating geologic application in their 

 solution are given below : 



1 Location of the Ashokan dam 



2 Sources of material for construction 



3 Crossing the Rondout valley 



4 The WallkiU valley 



5 Moodna buried valley 



6 Pagenstechers gorge and Storm King mountain 



7 The Hudson river crossing problem 



8 The Storm King-Break Neck cross section 



9 Foundry brook 



10 Sprout brook notch 



11 Peekskill creek valley 



12 Croton lake pressure tunnel 



13 Bryn Mawr siphon 



14 The new Kensico dam 



15 Kensico quarries 



16 New York city delivery tunnel 



In addition to these there are several questions of general bear- 

 ing in which the chief lines of argument and the chief basis of con- 

 clusion are essentially geologic. Although little wholly new data is 

 yet available on these particular questions from any direct work of 

 the aqueduct, yet it will add materially to an appreciation of the 

 far-reaching influence of established geologic data and geologic rea- 

 soning to enumerate some of them: 



17 Continental subsidence and elevation 



18 Crustal warping 



19 Postglacial and present faulting 



20 Underground water circulation 



21 Relative resistance of the different formations to corrosion by 

 aqueduct waters 



22 Structural materials 



Each of these problems or questions or topics is discussed sepa- 

 rately, so far as practicable. By adopting this plan, of course there 

 is a tendency to repetition but this to a certain extent is unavoid- 

 able. Some of it is overcome by suitable references to preceding 



