INTERESTING LOCALITIES OF AJIBIK QUARTZITE. 301 



adjacent to the <j;ranite. For the major part of the formation in this general 

 area the quartzites are very crystalHne. Distinct cores of the original grains 

 are found in onh' a few of the slides, and in these there is a sericitic back- 

 ground. Apparently when the original sandstones were nearly pure the 

 grains were pressed against one another so strongly as to result in granula- 

 tion. In the most crystalline phases there is a finely granular, intricately 

 interlocking background of quartz, in wliich is a small amount of sericite 

 and chlorite. In a less crystalline i)hase the original quartz grains still 

 exist, but they have been maslied, so that they are arranged with their 

 longer axes in a common direction. As usual, the rocks are cut by veins 

 of secondary cherty quartz. 



Broken bluffs. — Tlicre are numevt)us exposures of the Ajibik tormation in 

 sees. 30, 31, and 32, T. 48 N., R. 28 W. (Atlas Sheet XVIII). This is the 

 locality, referred to on pages 285-286, where the pecuUar infolding of the 

 quartzite and gneissoid granite occurs, the whole series of folds having 

 isoclinal dips and a westward pitch. At many places the quartzite formation 

 is exposed in contact with the granite, and here a conglomerate, bearing 

 numerous quartz pebbles, many large feldspar grains, and occasional small 

 granitic pebliles, is found. In some places the basal rock is a fine-grained 

 feldspathic quartzite, the granite having apparently been disintegrated and 

 broken into its constituent mineral particles. The conglomeratic parts have 

 a feldspathic quartzite base which is similar to the nonconglomeratic phases 

 of the rock. In many places the movement during the folding was so 

 great as to entirely granulate the quartz pebbles, different specimens show- 

 ing all gradations between coarse, vitreous vein quartz and completely 

 granulated, opaque, sugary quartz. In this mashed phase of the conglom- 

 erate little feldspar detritus is seen. If it was originally present it has 

 become decomposed. However, in those phases of the rock in which the 

 pebbles of quartz are transparent and vitreous the large detrital feldspai's 

 are abundant. In the intermediate phases the schist background contains 

 numerous roundish but flattened areas of quartz, the rock approaching in 

 its appearance a fine-grained augen-gueiss. Examined in thin section, 

 the quartzites are found to be feldspathic. In the less mashed phases the 

 feldspars have renewed their growth, and they present the best instances 



