of Lake Superior. 239 



It is black, light brown, shining gray, pale and dark green, and 

 even dark red, from the presence of iron. The gray colour arises, 

 probably, from an abundance of quartz, as that mineral, white and 

 crystalline, is plentiful in veins and imbedded masses. The green 

 is derived from chlorite, as we learn, from the tint and from its 

 frequency about the Peek and elsewhere. This greenstone inclines 

 to be soft, comparati'Jjly with other greenstones. I observed in 

 it no other foreign minerals than quartz and calcspar in veins and 

 imbedded masses ; and balls of reddish flint or jasper (Cape Mau- 

 repas). The stratification of this rock is generally very obscure ; 

 nearly the whole coast which it occupies, being an assemblage of 

 shivered and displaced masses, or of polished convex mounds 

 piled one above another, with their surfaces now and then also, 

 scarified by multitudes of minute lines including rhombic spaces. 

 It is remarkable for the number of irregular facettes with largely- 

 truncated edges, into which its surface is broken by the waves in 

 many places ; resembling certain imperfect artificial crystalli- 

 zations. Stratification in this rock does not seem to depend on 

 any particular constitution, for all the varieties are amorphous and 

 Blaty in places, without apparent cause for the one condition or 

 the other. Three miles south from Cape Choyye, the direction of 

 some stratified portions is EbN. distinctly, with a northern dip ; 

 and a similar position prevails, whenever discernible, throughout 

 the whole south side of Michipicoton Bay. At the place first 

 mentioned, the greenstone is cut by a dyke, or wall, 100 feet high, 

 50 feet broad, and of length unknown, of the shaly red rock, 

 observed some miles south of Gargantua, but here having in 

 addition to the green earth, horizontal layers of gray, green, and 

 white flint. The foot of this wall on the south is washed by a 

 noisy rivulet ; in every other direction it is surrounded by rubbish. 

 I believe it to be connected with the adjacent amygdaloid. My 

 opportunities did not permit a minute examination of it. At4| 

 miles and 5 miles from Michipicoton River, patches of conglo- 

 merate occur; the paste and nodule being both of this greenstone, 

 jn its various forms. They are of small extent. It is to be re- 

 marked, that when tiiis congloineratc (if such it be) becomes 



