of Lake Superior. 249 



stratification ; if it exist. Peek Island is of massive crystalline 

 red sienite, excepting (at least) one of the summits, -which is of 

 ■white quartz, containing hornblende in dots and small crystals, 

 which, although numerous, do not often run into each other *. 

 Among the calcareous debris of this island, I found a very large 

 and well preserved " bouclier," of the Asaph family of Trilobites. 

 From the bottom of the bay, N.W, of this island, the green- 

 stone of Michipicoton returns, as we continue on our tour, and 

 prevails along shore for sixteen miles and a half to about a mile and 

 a half east of the Black River. It is chiefly massive, but at places, 

 as near Cap a I'Ance de Boteille, it is in perpendicular layers, going 

 EbN. and N.E. It has numerous and distinct veins usually running 

 N.W. On the west side of the baj' beyond the wall of rock, con- 

 stituting Cap a I'Ance de Boteille, this greenstone is massive and 

 very pale. It often forms into balls from six to twelve inches in 

 diameter, and composed of thin concentric layers ; the structure 

 being marked by shades of green alternately pale and dark. The 

 Slate Islands on this coast have been visited by Lieutenant Bay- 

 field. They are of sienite and greenstone. The first resembles 

 that of the headland three miles N.E. of Peek Island ; and 

 the second cannot be distinguished from that of Michipicoton. 

 Mr. Bayfield found imbedded in the greenstone masses of crystal- 

 line limestone, two feet thick and twenty long; the terminations 

 being visible. These islands have also cliff's of an ochry red 

 coarse jasper, both hard and soft. I have some of the latter which 

 soils strongly. 



There now succeeds to this greenstone a granite, along the 

 main shore for twelve miles to my own knowledge ; and extending 

 further, as I learn from Lieutenant Bayfield, whose assistant- 

 surveyor, Mr. Collins (11. N.), has seen large tracts of these rocks 

 stretching as far as the west end of Nipigon Bay. The junction of 

 the granite with the greenstone on the east has not been examined. 

 It consists of white and red feldspar, some white quartz, but not 



* Lieutenant Bayfield, R.N., kindly gave me a specimen of this rock. 

 Vol. XVIIL S 



