56 



agglomerate schist, felsite, felsite schist and a limestone 

 and chert formation. 



Anorthosite. — This is a highly feldspathic saussuritized 

 gabbro or anorthosite which is areally disposed like a collar 

 about a central heart-shaped boss of granite. It is clearly 

 intrusive into the Keewatin, presumably in the form of 

 laccolithic lens which tapers westward. The intrusion 

 took place probably before the severe deformation of the 

 Keewatin, for the gabbro is itself intensely sheared locally. 

 The rock contains in places crystals of anorthite io 

 inches (25 cm.) in diameter. 



Laurentian. — This consists of a medium to coarse- 

 grained, light-coloured, biotite granite, locally poor in 

 biotite, and thereby grading into alaskite. It is intrusive 

 into the anorthosite, as well as into the Keewatin, and it 

 is believed, from the areal relations of the rocks, that it 

 attained its present position by arching up the lenticular 

 anorthosite sheet. 



Seine Series. — Within the area under discussion the 

 Seine series is represented chiefly by a great thickness of 

 basal conglomerate which grades upward into typical 

 quartzites and slaty schists. The conglomerate contains 

 a large amount of debris derived from the waste of Keewatin 

 rocks, but the pebbles and boulders, which are usually 

 well water- worn, consist chiefly of different varieties of 

 granite with a subordinate proportion of greenstone, 

 quartz porphyry and dark coloured chert pebbles. 



Particular Description of Points to be Visited. 



The Keewatin Series seen en route to the Mine. — 



A trail about half a mile (o-8 km.) long leads from Mine 

 Centre station southwest to the shore of Bad Vermilion 

 lake. Two ridges of Keewatin rocks are crossed by this 

 trail. One, just south of the village, consists of highly 

 schistose felsites and quartz porphyries, while the other, 

 which borders the north shore of the lake, is made up of 

 quite basic rocks, which are greatly deformed, owing, no 

 doubt, to their proximity to an area of intrusion. 



The lake is crossed in boats to the road leading to the 

 burnt remains of the Golden Star mine. Here Keewatin 

 greenstones and felsites are exposed on all sides. 



A trail, leading directly south across the hill, is followed 

 for about 300 feet (91.4m) to where it joins the mine road. 



