Reviews — Geological Survey of Canada. 521 



IV. — Geological Survey of Canada.. G. M. Dawson, C.M.G., 

 LL.D., F.R.S., Director. Annual Report (New Series), vol. viii, 

 Reports A, D, J, L, R, S, for 1895. With numerous plates and 

 maps. 8vo. (Ottawa : Dawson, 1897.) 



THE Summary Report (A, 154 pages) of the Geological Survey 

 Department, by the Director, treats of the progress and work 

 done in explorations and surveys, and in the museum, library, and 

 office generally, during 1895. 



In Report D (117 pages, with a map and three plates), J. B. Tyrrell 

 and D. B. Dowling describe the country between Athabasca Lake 

 and Churchill River, treating of the Laurentian, Huronian, Cambrian, 

 Cretaceous, and Pleistocene rocks, with the physical geography of 

 the region, especially along the several routes. 



Report J (181 pages, with two maps and eleven plates, besides 

 nine smaller figures), by Frank D. Adams, is a very interesting 

 resume of what is known of the geology and economic resources of 

 that portion of the Laurentian region lying north of the Island of 

 Montreal. The earlier observations by Logan and others are carefully 

 recorded, and the co-operation of colleagues is fully acknowledged. 

 The following general statement (p. 10), regarding the Arch^an 

 rocks here treated of, is important: — 



'• That portion of the area occupied by the Archfean is underlain 

 for the most part by a series of gneisses, presenting great variations 

 in both structure and composition, and with which are associated 

 crystalline limestones, quartzites, etc. These belong to the ' Grenville 

 Series ' of Sir William Logan, ^ and are of Laurentian age. In certain 

 parts of the area, however, there are great stretches of orthoclase- 

 gneiss, much more uniform in character, and without limestones and 

 quartzites. These are referable, in some cases at least, to the ' Funda- 

 mental Gneiss' of Logan, which was by him believed to underlie the 

 Grenville Series, and to form the basal meniber of the Laurentian 

 system. 



" Breaking through these gneisses, and in some cases interbanded 

 or interstratified with them, are several anorthosite masses, by far 

 the largest of these being that which for purposes of convenience 

 may be termed the ' Morin anoi'thosite,' and which comprises an area 

 of 990 square miles. Two important intrusions of acid rocks, one 

 of granite and the other of syenite, also occur in the district. 



" In the present Report the anorthosites are shown to be in- 

 trusions, and are separated from the Laurentian proper. The name 

 ' Laurentian ' is therefore made to embrace the Fundamental Gneiss, 

 which, although, so far as can be ascertained at present, essentially 

 igneous in origin, may possibly contain sedimentary material, and 

 the Grenville Series, which is composed of altered sediments, 

 associated with much injected igneous matter." 



I. — The Laurentian gneisses and their associated rocks are described 

 stratigraphically and petrographically (pp. 11, etc.). The Grenville 

 Series of banded, foliated, and faulted gneisses, and the associated 



1 " Geology of Canada," 1863, p. 839. 



