280 PETROLOGICAL ABSTRACTS AND REVIEWS 
percentage should have been taken higher. There are also new values 
for the angles between crystallographic a and c (8) and between a and 
6 (y). Query: Is not the anorthite cited as from the Bonin Islands, 
Japan, from Miyaké-jima instead ? 
SCHOFIELD, S. J. “The Origin of Granite (Micropegmatite) in 
the Purcell Sills,’ Canada, Dept. Mines, Museum Bull., No. 2, 
Geol. Series, No. 13, 1914, pp. 32, figs. 4, pl. t. 
The Purcell sills represent, according to the author, intrusions from 
a single intercrustal reservoir, which he apparently believes contained 
the magma already differentiated according to density, the relatively 
acid portion collected in irregularities and projections of the roof of the 
chamber and grading downward into more basic materials. Crustal 
movements produced fissures which tapped the reservoir at various 
levels, so that acid and basic materials would rise through separate 
fissures and spread between the overlying strata as sills. The sills 
themselves are simple or composite. The former solidified in the usual 
manner of intrusives; the composite sills differentiated in place, some 
of them having basic upper and lower contacts and an inner portion | 
which is more acid in the upper part and more basic in the lower. The 
composition of the sills may be slightly modified by assimilated material 
derived from included fragments or from the inclosing rock. 
SCHOFIELD, S. J. “The Pre-Cambrian (Beltian) Rocks of South- 
eastern British Columbia and Their Correlation,’ Canada, 
Dept. Mines, Museum Buill., No. 2, Geol. Series, No. 16, 1914, 
pp. 13, map I. 
ScHwarz,E.H.L. ‘The Granite Dykes of the 3,520 Foot Level, 
Kimberley Mine,” Trans. Geol. Soc. S. Africa, XVII (1914), 
3-23, fig. 1, pls. 4. 
SEDERHOILM, J. J. “On Regional Granitization (or Anatexis),”’ 
Congres géol. intern., Canada, 1913. Pp. 6. 
A study of migmatites and the processes by which granites work 
their way into adjacent rocks. 
SHAND, S. J. “On Veins and Inclusions in the Stellenbosch — 
Granite,” South African Jour. Scit., 1913, pp. 5, pls. 3. 
Describes various types of veins and inclusions in granite. 
