C URRENT PRE- CA MBRIA N LITER A TURE 525 



described by Smyth it comprises conglomerate, limestone, clay-slate, 

 and various basic volcanic and intrusive rocks. Because of the folding 

 of the series it is believed to be older than the Animikie strata of 

 Thunder bay. 



Animikie rocks occur in a small area in the southeast corner of the 

 Shebandowan sheet. They overlie unconformably the Keewatin and 

 Laurentian rocks, and from their stratigraphical relations to the over- 

 lying formation farther east on Lake Superior they are believed to be 

 of Lower Cambridge age. 



Comments.- — The mapping of this area of these sheets has been 

 largely lithological, the red granites and gneisses and their associated 

 rocks of various ages being mapped as Laurentian, and the green rocks 

 and the associated sedimentaries being mapped as Huronian. How- 

 ever, a distinct advance is made in seeing that some of the Coutchiching 

 rocks are no more than metamorphosed Huronian or Keewatin rocks. 

 This is a frank awowal that the Coutchiching series is a lithological, 

 not a structural unit. 



The Steep Rock Lake conglomerate was considered by Smyth and 

 Pumpelly as the basal portion of the Lower Huronian, and the under- 

 lying rocks as Archean. Mclnnes has mapped the underlying rocks as 

 Keewatin, and has included in them sedimentary and igneous rocks. 

 He has not separated from them sedimentary rocks which may be the 

 equivalent of the Steep Rock series. 



C. K. Leith. 



