Cushing — Geology of Clinton County. 



Ellenburgh. 



Series I. The gneisses enter Ellenburgh from the south, as three north- 

 easterly trending ridges. Ellenburgh mountain on the east, Panther mountain 

 in the centre, and on the west the less conspicuous ridge which forms San- 

 born's hill and West hill. The ridges are separated by wide drift-filled 

 valleys, in which occasional rounded and glaciated knobs of gneiss protrude 

 above the surface. The Ellenburgh mountain gneiss, and that in the valley 

 to the west of it, is the ordinary red, microperthitic gneiss of the Adirondack^, 

 very acidic, poorly foliated, and cut by numerous veins of coarse pegmatil : 



and quartz. The pronounced red color of much of the rock is found t< > I >t- 

 due to the infiltration of hematite between the grains and into the cleavage 

 cracks of the feldspar. 



The gneiss of Panther mountain and West hill is highly acidic and much 

 of it looks like a red granite, and contains nothing besides microperthitic 

 orthoclase and quartz. In the more gneissoid exposures a monoclinic 

 pyroxene of strong green color creeps in. Very basic bands are not very 

 numerous and are, so far as observed, hornblende-] >lagioclase gneisses, 

 generally having this same green pyroxene in addition. The magnetite grains 



