6io 



HENRY S. WASHINGTON 



Pulaskite {Foyaite^. — This is Williams's "gray granite," the 

 specimen coming from Braddock's quarry, on Fourche Moun- 

 tain. My analysis is given in I below, with that of W. A. Noyes 

 as quoted by Williams in II. The two are closely alike in all 



SiOs 



AI2O3 



FegOg 



FeO 



MgO 



CaO 



NagO 



KgO 



HsO(iio°+) 

 HgO(iio°-) 



60.13 

 20.03 



2.36 



1-33 

 0.76 

 0.87 

 6.30 



5-97 

 1. 41 

 0. 16 



CO,. 

 TiOg 

 ZrOg 



SO3 . 

 MnO 

 BaO. 



none 



I-IS 

 0.05 

 0.06 

 o. 14 

 trace 

 trace 



100.72 



99-56 



I. Pulaskite, Braddock's quarry, P'ourche Mountain. Washington, analyst. 

 II. Pulaskite ("Foyaite"), same locality. Noyes, analyst. Williams, c/. <:«?., p. 81. 



respects except Al^Og, which is about 2 per cent, higher in I, 

 as about i per cent, of TiO^, and a trace of PgOg must be 

 deducted from the AI3O3 of II. 



The analysis (i) calculates out as follows, and it is evident 

 that there is no essential difference between this rock and the 

 last mentioned. 



Foyaite. — What seemed to be an average specimen of the 

 occurrence at Diamond Jo quarry, Magnet Cove, was chosen for 

 analysis. No pyrite was visible, though the analysis shows a 

 trace of sulphur. One or two small garnets were seen in one 

 section, which mineral is not mentioned by Williams as an 

 accessory. 



