J 
MICROPEGMATITE IN PURCELL SILLS. 
13 
occurs in irregular plates having an average diameter of 0-25 
mm. Muscovite is present very sparingly and has a rod-like 
form. Magnetite, titaniferous magnetite in irregular nasses, 
apatite in idiomorphic crystals, together with very minute 
crystals of garnet, complete the mineralogy of the granite 
(micropegmatite.) The analysis of the granite (micropeg- 
matite) given below in column 1 is taken from Daly’s paper 1 — 
“The Secondary Origin of Certain Granites.” The analysis 
given in column 2 is the average analysis of granites of all periods 
by Osann and Clarke, given by Daly 2 . 
1. 
2. 
71-69 
69-92 
0-59 
0-39 
13-29 
14-78 
0-83 
1-62 
4-23 
1-67 
0-09 
0-13 
1-28 
0-97 
1-66 
2-15 
2-48 
3-28 
2-37 
4-07 

014 
0-78 
TT„0 * 
1-31 
0-07 
0-24 
0-13 
100-16 
2-773 
100-10 
2-660 
The calculation of the norm of the granite (micropegmatite) 
gives the following results : — 
Quartz 39-90 
Orthoelase 13-90 
Albite 20-96 
Anorthite 8-34 
Corundum . . 
Hypersthene 
Magnetite. . . 
Titanite 
99-12 
JR. A. Daly, Amer. Jour. Sci., 4th Ser. vol. 20, 1905, p. 193. 
2 R. A. Daly, Proc. Am. Ac. ol Arts and Sci. vol. 45, 1910, p. 21J. 
