NV. W. Portion of Lake Huron. 259 
gneiss having a northern direction, and the trap a south west 
course. 
These last named rocks are distinctly primitive, and are 
supported on the north and north east by others of that or- 
der, as for instance, for thirty-seven miles further to the east 
is a large trappose* formation, at the west end toes into 
greenstone, but at the eastern being nearly a pur ‘n- 
blende, highly crystalline, and rising in precisa which 
reflect a metallic lustre in certain positions. The islands of 
Cloche are of this substance, which occasionally be- 
comes a pois da and has given to this picturesque cluster 
its present na 
The rocks oe two hundred miles to the north east of this 
Spee are, with the exception of a little white tanrble in invari- 
'y small grained quartzose gneiss. 
Having now cursorily noticed the geology of the. eoualty 
in connection with the transition rocks of the north west por= 
tion of Lake Huron, I shall enter upon their description. 
__A greenstone in various modifications occupies the north 
main, from lon, 82° 42’ to the head of the Narrows of St. 
Joseph, a distance perhaps of twelve miles. In the exten- 
sive marshy bay, east of the broad omontery ts in the mid- 
| distance, this rock forms islets (either barren or 
fringed with a scanty 1 vegetation,) Fildes from the water in 
round and smooth ridges. Itis the same here as at the low- 
erend of the promontory, where it is a dark pbpepteti 
very compact, yet shewing a schistose tendency in its we 
ered portions. It is rather thickly studded with rolled 
masses of from one to eighteen inches in diameter, of the 
red Erosion ingredient in the Serpent rock—a curious fact. 
ome parts of this headland these fragments are so nue 
pats as to give to the rock the character of a 
rate; the imbedded substances being a large proportion. of 
the whole. | 
‘They disappear gradu: lly, bot entirely or nearly 20, and 
the form of a splintery greenstone slate 
sumed, differently colored, commonly of 2 a dak ra iw, 
_# With a south: woe cti fad vetiol ‘Aang te one lve 
e 
+ The want of appellations for the. ferent localities i is Fae felt in 
speaking of unfrequented countries. 
