STRUCTURAL FEATURES OF THE PRE-CAMBRIAN 193 



these beds may not belong to this series, but may be fine-grained 

 sediments of the Nemenjish series. The beds dip toward the north, 

 but a consideration of the relative movement of the beds inferred 

 from the shape of the drag folds showed that they form the south 

 limb of an overturned anticline. It seems possible therefore that 

 these beds are the south limb of the anticline of which the Brock 

 sediments form the north limb. If so, the axial plane of this large 

 fold dips to the north. 



The succession in the Brock area therefore in order of age appears 

 to be: 



Mica and hornblende schists 



Grits 



Conglomerate 



Uncomformity 

 Green schists and basalts 



Lucky Strike area. — The Lucky Strike area (Fig. 10) lies at and 

 above the junction of Lucky Strike creek with the south branch of 

 the Broadback River. Here, as in the Brock area, the youngest 

 rocks are granites, which intrude a series of sediments, consisting 

 of conglomerate at the base, passing upward into arkose or grey- 

 wacke, and then into muscovite schists which probably represent 

 impure sandstone. Beds which may have overlain these have been 

 cut off by the granite. All the beds are much deformed, although 

 not so much as in the Brock area. The following pebbles were 

 observed in the conglomerate: hornblende granite, quartz biotite 

 schist, anorthosite (one only) , hornblende schist, made up almost 

 wholly of hornblende needles; hornblende schist containing 30 to 

 40 per cent plagioclase, quartz porphyry, bedded chert, and others 

 which were originally of softer rock and are now so deformed as to 

 render their original nature indeterminable. Many of these pebbles 

 are recognizable as having been derived from the lava series, so 

 that the conglomerate is evidently unconformable above it. The 

 harder pebbles have suffered little or no deformation and are well 

 rounded, indicating long attrition before deposition in their present 

 position. 



The older series is not well exposed in this locality. Directly 

 underlying the conglomerate in one place is found a garnetiferous 



