GEOLOGY OF THE LUZERNE QUADRANGLE 47 



Hudson valley between Stony Creek station and Thurman station, 

 or along the deep valley o£ Stewart brook, though each of these 

 valleys suggests carving out of the rocks along a fault zone. 



Age of the faulting. That some Adirondack faulting took place 

 in Precambrian time has been rather well established, but, so far 

 as definitely known, such fractures are of minor importance. No 

 positive evidence for such faulting was found in the Luzerne quad- 

 rangle. It seems quite likely, as Gushing has suggested, that con- 

 siderable faulting took place during, or toward the close of, the 

 Paleozoic era. 



Any fault scarps, ridges or valleys which may have been pro- 

 duced by the close of Paleozoic time must have been nearly or quite 

 obliterated by the long subsequent time of erosion. If so, how do 

 we account for the present Adirondack ridges and valleys which 

 follow the fault lines or zones? Accompanying the uplift of the 

 late Mesozoic or early Cenozoic peneplain of the Atlantic coast 

 region, or following it, there was either new faulting, or renewed 

 movement along old faults, or old faults were not affected by new 

 movements. How much is new faulting, and how much renewed 

 faulting along old fracture lines or zones is not known, but it is 

 quite certain that considerable faulting in the eastern Adirondacks 

 must date from the uplift of the peneplain just mentioned as shown 

 not only by fault scarps in homogeneous rock, but also by the dis- 

 tinctly down faulted block between Hadley hill and West mountain. 

 Conspicuously tilted fault blocks, like those in parts of the North 

 Creek quadrangle, are not well represented in the Luzerne 

 quadrangle. 



GLACIAL AND POSTGLACIAL GEOLOGY 

 General Statements 



It should be understood that the writer has made no careful 

 detailed study of the Glacial and Postglacial geology of the Luzerne 

 quadrangle. His purpose is merely to record and tentatively inter- 

 pret many observations made during the study and mapping of the 

 old rock formations. 



It is well known that, during the ; great Ice Age of the Quater- 

 nary period, all of New York State except portions of the extreme 

 southern side was buried under a sheet of ice. That this great 

 glacier was thick enough to bury even the highest summits of north- 

 ern New York is proved by the presence of glacial pebbles and 

 boulders at or close to the highest points on the mountains. This 



