136 



A. F. BUDDINGTON 



in diameter and are so intermingled with smaller ones as to make 

 up almost the entire bulk of the rock. The pinitized groundmass 

 possesses a waxy luster, dark dirty-green in color, and is quite soft. 

 The parting of the pinite is in general parallel to the cleavage of 

 the rhyolite, although in detail it is a series of curving shell-like 

 scales, owing to its parting following the circumference of the more 

 resistant spherulites. An analysis of this matrix is given in this 



Fig. 4. — Pinite {p), replacing portions of the matrix of a spherulitic rhyolite 



Journal on p. 137 (No. 7). Very rarely pinite is found along the 

 original contraction cracks of the spherulites or at the heart of 

 a spherulite. Patches, lenticels, and minute veins of pinite are 

 found throughout the rhyolite flows and agglomerates, often repla- 

 cing the matrix of spherulitic zones (228 G 1 k) or certain flow lines 

 (222 E 2 x). 



In the valley of Harbour Main Brook, among a series of rhyolite 

 flows and tuffs, tuff beds up to 75 feet thick have been partially 

 altered to pinite, and spherulitic rhyolite flows up to 30 feet thick 

 are streaked and banded with pinite. These rocks have been 



