PRE-CAMBRIAN OF NORTHERN ONTARIO AND QUEBEC 315 



well as a few pebbles of granite and syenite. The volcanics 

 observed in the basal conglomerate include basalt, andesite, rhyo- 

 lite, iron formation, red jasper, and various cherts and tuffs, many 

 of them possessing well-defined bedding. Schistosity in the 

 pebbles was observed in one place only, near Kenogami station on 

 the Timiskaming and Northern Ontario Railway, where a few 

 pebbles of a peculiar volcanic breccia are sheared. (This state- 

 ment naturally applies only to such bodies of conglomerate as have 

 not been sheared as a whole. Where this has taken place the 

 pebbles are to be found in all stages of mashing.) The pebbles in 

 the basal parts of the conglomerate are very well rounded, thus 

 evidencing considerable wear before final deposition. 



Wilson has argued that the presence of pebbles of the volcanics 

 does not constitute proof of unconformity, and while he does not 

 exclude the possibility of unconformity he regards it as possible 

 that the conglomerates do not represent any long erosion interval. 

 It is true that the presence of the lava pebbles is not full proof of 

 unconformity, and the writer will go farther and admit that even 

 the granite pebbles do not necessarily indicate unconformity, 

 since he has found a few granite pebbles in coarse tuflfs inter- 

 stratified with Keewatin basalts. The conclusive evidence of uncon- 

 formity is found in the presence of pebbles of iron formation, 

 bedded chert, etc. These are water-laid sediments, as is clearly 

 shown by their thin uniform bedding, their frequent association 

 with thin-bedded tuffaceous elastics, and their association in other 

 places with pillow lavas, which are now commonly recognized as 

 subaqueous extrusions. The presence and association of these 

 pebbles in the Timiskaming conglomerate indicates conclusively 

 that before the conglomerate could have been laid down there must 

 have been uplift, some folding, and erosion of the underlying rocks. 

 Unconformity is thus proved. 



Relations to the granites. — The relation of the Timiskaming 

 series to the ordinary granite of northern Ontario that contains a 

 great deal of free quartz is not yet known, as such granite is not 

 found in contact with the Timiskaming series at any known 

 point. But granites of this type intrude the Timiskaming series 

 in northern Quebec. At the contacts the sediments are more or 



