rETKOGEAPIIICAL CHARACTER OF THE AJIBIK QDARTZITE. 287 



explained iu another connection by the transgression of tlie sea from tlie 

 east. The Ajibik area in contact with the Archean extends west from 

 the Teal Lake quartzite range on the north, and from sec. 35, T. 47 N., 

 R. 26 W., on the south, to the west end of the distric-t. Also there is liere 

 included the area in sec. 29, T. 47 N., R. 26 W. The eastern area comprises 

 the remainder of the formation. 



Where the formation rests directh' upon the Archean its basal part is a 

 conglomerate or recoraposed rock, the material of which is derived mainly 

 from the immediately subjacent rocks. In short, the conditions of for- 

 mation are the same as, and the phases of the basal rock identical with, 

 those of the Mesnard cpiartzite, described on page 223. This is entirely 

 natural, as the two are in fact but parts of the first deposit of the trans- 

 gressing sea. The basal conglomerates, slates, and graywackes for this 

 part of the area quickly grade up into (piartzite which does not differ from 

 that of the remainder of the formation. 



In the eastern part of the district, as the Wewe slate passes into the 

 Ajibik quartzite there is usuall}^ an intermediate phase, or interstratifica- 

 tions of the two. In many places the slate varies into a coarse gray wacke, 

 this into a feldspathic quartzite, and this into the ordinary quartzite. In 

 other cases the transition phase is a white or green novaculitic ([uartzite. 

 AVith these are sometimes red and brown iron-stained kinds. In places the 

 nonferruginous and ferruginous varieties show the most curiousl}' complex 

 relations, one appearing in the other in the most indiscriminate manner, as if 

 in extremely irregular inclusions or patches. The iron staining is evidently 

 a secondary process, and the differing effects have been produced by the 

 varying depths to which the solutions have penetrated. In one exceptional 

 locality, in sec. 6, T. 47 N., R. 25 W. (Atlas Sheet XXXVII), the l^asal 

 member of the quartzite is a conglomerate interstratified with slate, the 

 fragments of the conglomerate l^eing mainly from the Wewe slate. 



The central part of the formation in its ordinary phases is a typical, 

 rather pure, vitreous quartzite. In some places this quartzite becomes 

 conglomeratic and bears small pebbles of white quartz or red jasper. In 

 other places it is interstratified with l^elts of mica-slate or graywacke. 

 In many places the formation was subjected to dynamic forces. In the 



