PRE-CAMBRIAN ROCKS OF NEWFOUNDLAND 



459 



As seen in thin section the texture is usually microgranitic or an 

 irregular polarizing aggregate of quartz and feldspar. Spherulitic, 

 axioHtic, and microspheruHtic textures are common, and rarely a 

 felt of microlitic feldspars in a groundmass of quartz is observed. 

 A micrographic texture characterizes portions of an eutaxite from 



Fig. 4. — Very coarsely spherulitic rhyolite; the largest spherulite is twenty-two 

 inches in diameter; about five and one-half miles south of Manuels, Conception [Bay. 



near Avondale. A chemical analysis of a specimen from a 50-foot 

 rhyolite flow follows. The rock is a dense, red, banded felsite with 

 a microfelsitic to finely microcrystalline and micropoikilitic texture. 



TABLE II 



Chemical Analysis of Rhyolite from Flow at Manuels 



SiOj 76.24 



AI2O3 13 . 94 



Fe^O, 8q 



FeO. 



MgO. 



CaO. 



•13 



.27 

 1.07 



Na,0 2 . 55 



K2O 4.95 



H.0+ 15 



H,0- 03 



Total 100 . 22 



