6o 



NEW YORK STATE MUSEUM 



Table 5 Thin sections of gabbro 





 w 



d 



0) 





 '5i 



a) 



C 

 ■ H 





 



1 

 "a 



5 



1 



u 



0) 



ft 





 



a 

 g 







s 



CD 



a 



U 







<u 



ll 



H 



a) 





c 

 



26 



53 



54 



52 



55 



5 c I 

 4 c 9 

 4C3 

 4 m 2 

 14 g 2 



Ol.-Lab. so 

 An .-Lab. so 

 An.-Lab. so 

 An .-Lab. so 

 Lab. so 



3 



12 



5 



20 



10 



5 



20 

 12 

 13 



17 



I 



24 

 15 

 25 



I 

 7 



'little' 

 little 



4 



I 



ID 



14 

 10 



I 

 I 



little 

 little 

 little 

 i 

 little 



J 



little 



little 













Nos. 26, 53 and 64, from Pulpit mountain gabbro mass ; no. 52, from 

 southern side of gabbro 2^ miles south-southeast of Upper Jay; no. 55, 

 from gabbro at southern base of Catamount mountain. 



Most of the Pulpit mountain gabbro mass is gneissoid, only a 

 relatively small portion of the interior being nonfoliated and with 

 a diabasic texture. Nos. 26, 53 and 54 of table 5 are from this 

 stock. 



The largest body, from 2 to 2}^ miles south-southeast of Upper 

 Jay, lies only partly within the limits of the quadrangle. Most of 

 the rock is medium to moderately coarse grained with good dia- 

 basic texture, and a gneissoid border facies is more or less well 

 developed. It is an olivine gabbro (see no. 52 of table 5). A 

 small diabase dike, with nearly north-south strike and dip 60 

 degrees east, sharply cuts the gabbro near the southern margin. 



A small diabase dike sharply cuts the small gabbro mass i mile 

 west of East Kilns. 



The other gabbro masses are quite typical in every way. The 

 gabbro at the southern base of Catamount mountain clearly exhibits 

 its relations to Whiteface anorthosite, Keene gneiss, and granite, 

 all three of which it sharply cuts. 



Diabase Dikes 



General features. Without counting two or more dikes close 

 together within practically single outcrops, sixty-one diabase dikes 

 were found within the quadrangle. These are all located and num- 

 bered on the accompanying geologic map. Without question still 

 others exist, but they are either effectually concealed or they 

 escaped detection in the rough wooded country. Such diabase 

 dikes are known to occur throughout the Adirondack region. They 

 are the youngest of the Precambrian rocks, and they always sharply 



