318 THE VERMILION IRON-BEARING DISTRICT. 



sediments. After leaving Flask Lake one finds, in traversing the portage 

 between Flask Lake and Snowbank Lake, a number of good exposures 

 showing a rather coarse greenstone conglomerate, which is well developed 

 in this vicinity. These conglomerates yerj rarely contain any pebbles of 

 granite or jasper, most of the fragments being of greenstone, and in this 

 respect the conglomerates are different from those occurring farther north 

 and west, nearer Moose Lake. They have also suffered more from meta- 

 morphism, since they are nearer to the main Snowbank granite massive 

 which has intruded them. 



The northwest shores of Disappointment Lake afford the best places 

 in the Vermilion district for studying the Ogishke conglomerate. At the 

 time of the survey here reported the country had been recently burned 

 over and the hills were practically bare. There was a little scanty 

 vegetation, but one could see bare rock exposed in great flat or slightly 

 rounded surfaces nearly everywhere. Great beds of coarse bowlder 

 conglomerates were exposed, grading into finer-grained conglomerates, 

 and these through graywackes into slates, to be succeeded by a repetition 

 of these gradations. The strike of the bedding is very uniformly N. 20° W., 

 the dip varies from 75° west to 80° east, but is very commonly nearly 

 vertical. The conglomerate at Disappointment Lake differs from the typical 

 Ogishke in respect to the absence from it of the jasper which is so common 

 in the typical Ogishke. No pebbles of this kind were found on Disappoint- 

 ment Lake. The pebbles consisted chiefly of varieties of granite and 

 porphyry, and especially of numerous varieties of greenstone. In fact, 

 many of the beds of conglomerate consisted exclusively of pebbles of 

 different varieties of greenstone, ai^d the matrix between the pebbles 

 consisted of finer detrital matter derived from the same source. The 

 conglomerates had been intruded by a number of dikes, basic as well 

 as acid, and they had been metamorphosed by the Snowbank granite, 

 from which the granite dikes are offshoots, and subsequent to this 

 metamorphism had been further metamorphosed by the great Kewee- 

 nawan gabbro. Consequently the nearer one approaches the Snowbank 

 granite the greater the metamorphism, and the changed character of the 

 sediments is still further increased as one goes along the margin of the 

 granite mass "and approaches nearer to the gabbro. In some jjlaces, even at 

 considerable distances from both of these intrusive rocks, the conglomerates 



