24 NEW YORK STATE MUSEUM 



hundred feet below sea level has been proven. Faults and minor 

 folds are still more numerous throughout the region than could be 

 seen on the surface. Decayed conditions in crush zones, and in 

 porous layers favorably situated, are known to exist to great depth 

 locally and at depths of less than three hundred feet there are many 

 narrow zones of rock in such condition. Rarely, near the surface, 

 there are extensive occurrences of residuary matters. The tunnel 

 near Garrison in the Highlands passes through over five hundred 

 feet of such rock still preserving the typical formational structure, 

 but so soft that it requires as substantial timbering as would so 

 much glacial drift. 



It is the deep explorations, however, that promise the most addi- 

 tional data. The courses of deeper water circulation and its effect 

 on different rock formations are shown at many places. The gran- 

 ites beneath the Hudson river at Storm King mountain show strain 

 to such extent that, in certain zones, slabs crack off from all surfaces 

 as soon as exposed. This rock is penetrated at a depth of one thou- 

 sand one hundred feet below sea level and all but about five hundred 

 feet of the distance from one side to the other has been exposed. 

 No noteworthy crush zone or fault or other special weakness line 

 has yet been discovered in that section, but jointing is strong and 

 abundant. 



The tunnels show more clearly than the surface exposures the 

 intrusive nature of the granites of the Highlands. One new belt of 

 interbedded limestone and associated quartzite schist has been ex- 

 posed by the aqueduct open cuts. Simple chemical tests on a great 

 many samples of Fordham gneiss from New York City explorations 

 have shown a much wider occurrence of lime carbonate in them 

 than was formerly suspected. Many layers not connected with lime- 

 stones at all carry a strong lime content. 



A hurried reconnaissance and comparison has been made of the 

 granite and limestones of the vicinity of Mounts Adam and Eve in 

 the Goshen quadrangle and of the belt toward Franklin Furnace. 

 The granites of that district are strictly of intrusive character. They 

 cut and include older gneisses which themselves contain inter- 

 bedded limestone layers in every way comparable to those of 

 the region along the Hudson. A short reconnaissance of a small 

 area in the Franklin quadrangle mapped as Pochuck gneiss was 

 made for purposes of comparison with the Hudson river district. 



In Orange comity Dr Henry B. Kiimmel has made observations 

 which have an important -bearing on the tectonic structure of the 



