84 • Reviews — Timiskaming County, Quebec. 



raised marine clay banks along the Tavoy estuary. The tin-bearing 

 beds of the Kanbauk area must have been laid down in a rapidly 

 sinking valley, but recent movements of the land were in an upward 

 direction. The author gives a list of localities in which he suggests 

 that prospecting is likely to give good results. 



E. H. E. 



VII. — Timiskaming County, Quebec. By M. E. Wilson. Memoir 

 103, Canada Department of Mines, lS T o. 86, Geological Series. 

 pp. 197, with 16 plates, 6 text-figures, and a map. Ottawa, 

 1918. 



f nHIS well-produced memoir is a general statement of the results 



T 



western part of the province of Quebec. Besides the special and 

 detailed descriptions of the local geology of Timiskaming County, it 

 contains a good general account of the geology of the Ottawa basin, 

 which comprises rocks of early and late Pre-Cambrian and Lower 

 Palaeozoic age. The former are included by the author in the Basal 

 Complex, Huronian, and Keweenawan groups, while the Palaeozoic 

 sediments contain representatives of the Ordovician and Silurian 

 systems. 



Timiskaming County lies wholly within the Laurentian plateau 

 and possesses in part the rocky-lake topography characteristic of 

 that region, but part of it is occupied by plains of Post-Glacial 

 lacustrine clay, forming what is generally known as the " clay belt". 

 There are also numerous linear gorge-like valleys, which are 

 believed to be of tectonic origin. 



The lowest rocks seen in the area are the gneisses and limestones 

 of the Grenville series. These are succeeded by the sediments and 

 igneous rocks, extrusive and intrusive, of the Abitibi series, into 

 which are intruded the Pre-Huronian batholiths. Upon these lie 

 unconformable the Cobalt series, consisting of conglomerate, arkose, 

 greywacke, and argillite. The Keweenawan rocks are mainly of 

 a basic character, ranging from olivine-gabbro to syenite-porphyry. 



The Ordovician Black Eiver Limestone is probably separated by 

 an unconformity from the calcareous sandstones and limestones of 

 the Niagara series, the youngest formation represented in the 

 district, with the exception of the Glacial and Post-Glacial deposits. 

 Hence it is seen that the geological sequence in this area is 

 remarkably incomplete. 



The Cobalt series shows some features of considerable interest, 

 since many of its members are believed to be of glacial origin : they 

 show a remarkable similarity, allowing for natural processes of 

 alteration, to the deposits of the Pleistocene continental ice-sheets, 

 laid down under lacustrine conditions in the outer zone of an area of 

 glaciation. 



The deposits composing the clay belt consist chiefly of finely 

 laminated beds of clay and silt with occasional thin layers of calcium 

 carbonate, sometimes passing into sandy beds. These were probably 

 laid down in a great glacial lake, which is provisionally called Lake 



