8 GEOLOGICAL SURVEY, CANADA. 



series of rocks hitherto unrecognized in the Arclisean of that part of 

 Canada. This fact has attracted a number of geologists to Steep- 

 rock lake, and several references to the series are to be found in 

 the literature of the region. The general question raised in all of 

 these is the relation of the Steeprock series to the Keewatin. 

 Smyth made perfectly clear that the Steeprock series rested uncon- 

 formably upon his basement complex with a basal conglomerate 

 reposing upon an eroded surface. But in that basement complex 

 he recognized no Keewatin, but only those granites and gneisses 

 which are usually referred to as Laurentian. The areal limits of 

 the Steeprock series to the south and southwest were left unde- 

 fined. In these directions, however, the rocks of the series are 

 continuous with and indistinguishable from the Keewatin, and to 

 any geologist who became familiar with this fact the whole implica- 

 tion of Smyth's interpretation of the geology was that the series 

 was in part a local facies of the Keewatin and in part a normal 

 facies, and that the Keewatin was, therefore, unconformable upon 

 rocks of the Laurentian type and habitus. 



Mr. W. H. C. Smyth,' after an examination of the series, 

 accepted Smyth's descriptions and classification, saying : ' The work 

 done by the writer in connexion with the rocks of this series suggests 

 no important modification of them.' But he expressed the opinion 

 that the Steeprock series was later than the Keewatin; a question 

 upon which H. L. Smyth was silent. He did not, however, locate 

 the contact of the Steeprock and Keewatin : ' The unconformity 

 above the Keewatin schists of the Seine river to the southwest is 

 not at all obvious. Lithologically the green traps and schists of the 

 two series are strikingly similar and could not probably be separated 

 by the most careful study.' 



Coleman,^ in 1897, regarded the Steeprock series as part of 

 the Keewatin. He says : ' The water-formed elastics of the Kee- 

 watin are of great variety, including limestones, quartzites, slates, 

 grits, graywackes, breccias, and pebble and boulder conglomerates. 

 The limestones are, however, of limited extent, being found in any 

 thickness only at Steeprock lake, 70 miles east of Rainy lake, 

 where there is a small area differing both petrographically and 

 structurally from the rest of the region. These limestones have a 



1 BtoII. G.S.A., Vol. 4, 1893, pp. 34i.347. 



2 Bull. G.S.A., Vol. 9, p. 225. Also Eept. Bureau of Min«s, Ontario, 

 Vol. VII, Pt. II, 1898, p. 152. 



