572 REVIEWS 



Reports on a Portion of the Algoma and Thunder _ Bay Districts, 

 Ontario, by W. J. Wilson, and On the Region Lying North oj 

 Lake Superior between the Pic and Nipigon Rivers, Ontario, 

 by W. H. Collins. Canada Department of Mines, Geological 

 Survey Branch, 1909. 

 In the region covered by the first report the rocks are chiefly Laurentian, 

 consisting of granites and gneisses. These are interrupted in considerable 

 areas by hornblende and biotite schists with diabase dikes, which are classed 

 as Keewatin. Microscopic descriptions of these rocks made hy G. A. Young 

 are given. In the north of the region are nearly flat-lying dolomitic rocks 

 classed as Cambro-Silurian and Silurian. A list of fossils from these forma- 

 tions identified by J. F. Whiteaves is appended. 



The entire region covered by the second report is composed of pre- 

 Cambrian rocks, all of which are crystalline except in the west, where 

 comparatively unaltered sediments are to be seen. According to litho- 

 logical characters the rocks are placed in four groups: (i) Laurentian, 

 an intimate association chiefly of granites and gneisses of various sorts; 



(2) Keewatin, dark green, gray, or black schists largely eruptive in nature, 

 and sheared porphyries containing much secondary chlorite and pyrite; 



(3) Keweenawan, brick-red dolomites; and (4) eruptives, hornblende and 

 eleolite syenites, diorite, pegmatites, and diabases. 



Minerals of economic importance occur in considerable variety but 



few deposits of valuable extent have been found. 



In both reports considerable attention is given to the routes followed 



and the rock exposures studied. 



E. R. L. 



The Coal Fields oj Manitoba, Saskatchewan, Alberta and Eastern 

 British Columbia. By D. B. Downing. Canada Department 

 of Mines, Geological Survey Branch, 1909. 

 This report is a concise statement of the area and probable contents 

 of the various coal fields of the middle portion of Canada. There are 

 three important coal-bearing formations, all belonging to the Cretaceous 

 period and separated by shales of marine origin. These are the Kootanie, 

 the Belly River or Judith River (Montana), and the Laramie. The char- 

 acter of the coal ranges from lignite to anthracite, the anthracite area being 

 that of the Cascade basin. The areas in which coal is to be found are 

 described briefly; analyses already published are collected in the form of 

 tables and selected analyses of other North American and foreign coals 



are added for comparison. 



E. R. L. 



