376 Reviews — Geological Survey of Canada. 



E, E ^7- I E "W" S . 



I. — Geological Survey of Canada. A. P. Low, Deputy Head and 

 Director. Report on the Geology and Natural Kesourees of the 

 Area included in the North- West Quarter-Sheet, No. 122, of the 

 Ontario and Quebec Series, comprising Portions of the Counties of 

 Pontiac, Carleton, and Renfrew. By P. W. Ells. [With a 

 Paloeontological Appendix, by H. M. Ami.] 8vo ; pp. 71, with 

 map. Ottawa: S. E. Dawson, 1907. 



^PHE area here described, the "Pembroke Sheet" of the map, lies 

 \_ to the west of No. 121, the " Grenville Sheet," and has an area 

 of 3,466 square miles. Its eastern boundar}- is not far from the 

 Gatineau river, north of Ottawa city, and its south-western portion is 

 traversed by the Ottawa river from a point about thirty miles west of 

 Pembroke to within ten miles of the city of Hull. The rock formations 

 comprised in it are as follows : — 



Palaozoic Formations. 



Trenton Limestone. 



Black River Limestone. 



Chazy Limestone and Shales. 



Calciferous Dolomite. 



Potsdam Sandstone. 



Crystalline Mocks, including : — 

 Granite and Granite-gneiss. 



Gneiss, Quartzite, and Limestone of the Grenyille Series. 

 Anorthosite and other Igneous Rocks. 

 Post-Pliocene Deposits. 



The crystalline rocks, which fill the most important place in the 

 area surveyed, comprise the so-called fundamental gneiss and associated 

 granite, and the upper series of banded gneiss with quartzite and 

 crystalline limestone, the latter having the greatest development in 

 the eastern half of the area surveyed, the older series in the western. 

 Here the limestone is generally absent, but when present it is in the 

 form of narrow bands resting on well-bedded quartzose gneiss, which 

 in some places, the Coulonge river, for instance, forms cliffs, in which 

 it presents the bedded aspect of the Potsdam Sandstone. 



The fundamental gneiss is well seen in the western part of the ai'ea, 

 where it has, in some places, a well-defined gneissic structure, but the 

 rock is often granitic. These rocks apparently represent the oldest 

 known geological formation of the Ottawa district. In that portion 

 of the gneiss associated with the quartzite and limestone in the area 

 adjacent to the Gatineau river, deposits of mica, apatite, and graphite 

 are numerous and valuable. The limestones generally occur in basins 

 and represent the upper part of the Arehoean rocks. They usually 

 rest upon well-bedded masses of white quartzite. 



In summing up the results of his investigation of these crystalline 

 rocks Dr. Ells remarks that "from an examination of all the features 

 of the problem it has now been generally accepted that the Laurentian 

 should be confined as far as practicable to the fundamental granite- 

 gneiss, that the rocks of the Grenville and Hastings series should be 



