94 NEW YORK STATE MUSEUM 



The strongest point in favor of the Storm King crossing was the 

 evidence that the tunnel beneath the Hudson would lie in a single 

 type of rock, the Storm King granite, whose structure is more mas- 

 sive and uniform than any of the others. 



There seemed to be less danger also from faulting in that partic- 

 ular spot than most other places along the Hudson river. The fault 

 question indeed was one of the most vital in the problem. All but 

 one other of the locations studied involved certainty of weakness 

 within the Hudson river gorge itself. The quality of rock and the 

 faulting problem were, therefore, the most decisive factors. 



A second-choice location was between Crows Nest and Stony 

 Point and as conditions are now known there is no particular rea- 

 son to disfavor such a crossing, as far as geological behavior is con- 

 cerned. A third possible crossing, near West Point, involved a 

 great crush and fault zone, which the river follows from West Point 

 to Fort Montgomery. 



All the proposed crossings north of the Highlands involved tun- 

 nels in the Hudson River-Wappinger-Poughquag series with a 

 certainty of many faults and other structural difficulties and a very 

 long stretch under pressure. No place .superior to the Storm King 

 location was available thcefore on the most important counts, li 

 was formerly assumed b\' many geologists and engineers that thz 

 Hudson river followed a fault line and that the gorge probably could 

 not be crossed without encountering the troubles of the accompany- 

 ing fault zone. Studies made at the time this ]jroblem was under- 

 taken, however, indicated that most of the lines of the great fault 

 .'System run diagonally northeast-southwest, crossing the river rather 

 than following it, and that this is strictly true in the section between 

 Stonn King and West Point. Later explorations and observations 

 made during the actual construction of the tunnel have fully sus- 

 tained this conclusion so far as the Storm King-Breakneck locality is 

 concerned. With regard to the other places, of course, no additional 

 information is available. 



After choice of location, however, the chief controlling question 

 was the depth of the preglacial channel. Before construction could 

 begin and even before final estimates could be made, a particular 

 depth for construction had to be determined upon, a matter of no 

 easy solution. 



It was supposed by many engineers that the bottom of the Hudson 

 had been determined at New York City as approximately 300 feet 

 below sea level ; but when this question was studied fully, it became 



