Eevieus — Geological Survey of Canada. 179 



tlie area, into well-marked gneiss, the latter evidently a pliase of 

 the granite produced by stress and incipient flow. The prevailing 

 aspect of the rocks of the Coutchiching series in this section is that 

 of stratiform, fine and coarse gneisses, the coarser intrusive through 

 the finer. The iiner gneiss is identical with the Coutchiching series 

 of Rainy Lake and probably represents its eastward extension. The 

 Keewatin is made up of a number of rock types varying from 

 extremely basic, igneous masses and their derived schists, to acid 

 quartz-porphyries and the schists produced by their shearing. The 

 Steep Rock Series, occurring about Steep Rock Lake, are believed 

 to be of later age than the greater mass of the Keewatin strata, as 

 they overlie unconformably the rest of the Archaean, occupying 

 a position below the Cambrian and above the great bulk of the 

 Keewatin. The Animikie rocks, which occupy a limited area in 

 tlie south-eastern corner of the region, overlie unconformably the 

 Archaean rocks wherever they have been seen in contact. From 

 their stratigi-aphical relations to the overlying formations further 

 east on Lake Superior, they are believed to represent the lower 

 beds of the Cambrian. They consist of black and green slates with 

 calcareous and cherty bands. 



The glacial geology and economic geology of the region are 

 described, the minerals including iron, gold, and silver, with others 

 in insufficient quantities to be commercially valuable. 



Report I, by Mr. A. E. Barlow, deals with the geology and 

 natural resources of the area included in the Nipissiug and 

 Temiscaraing map-sheets, comprising portions of the district of 

 Nipissing, Ontario, and the county of Pontiac, Quebec. It is 

 accompanied by two maps, each on a scale of four miles to one 

 inch. The area represented in each map measures seventy-two 

 miles in length from east to west, and forty-eight miles from 

 north to south, thus embracing an area of 3,456 square miles, or 

 a combined area of 6,912 square miles. The several geological 

 systems and formations represented in the region subjacent to the 

 Pleistocene supei'ficial deposits are as follows, in descending order : — 



Pat vci ^ Silurian : Niagara. 



■ \ Cambro-Silurian : Trenton ; Birdseye and Black River. 

 A I Huronian. 



( Laurentian : Diorite -gneiss and granite-gneiss. 



The Archasan rocks of the region may be separated into two 

 great subdivisions, that of the so-called Lower Laurentian and the 

 Huronian. The Laurentian is composed of a series of massive or 

 schistose, and usually evenly foliated, crystalline rocks, the latter 

 "being commonly referred to as ' gneisses.' The latter are separable 

 into two divisions according to the prevalence of orthoclase or 

 plagioclase as the felspathic constituent. Of the two types, granite- 

 gneiss and diorite-gneiss, the former is by far the most abundant, 

 and often passes by insensible gradations into massive, reddish 

 granite in which little or no trace of foliation can be detected. 



The Huronian rocks are generally clastic in composition, appear- 

 ance, and microscopic structure, in marked contrast to those of 



