256 Geology and Mineralogy of the 
and are round and smooth. ey are seen every where 
but are collected principally in the interior of the coasts and 
islands either in confused heaps, or in parallel ridges, and 
crowning the highest acclivities in great numbers and the frag- 
ments are of various dimensions. They belong almost exclu- 
sively to the older orders of rocks, and are therefore of @ 
northerly origin. Granites, gneiss, mica slate, and porphyries 
evail, of kinds which I never saw in situ, although [ have 
skirted the north shore for two hundred miles, and have trav- 
ersed the wilderness to the east north east for six hundred 
miles. Mica slate I never met with in a fixed state, excepting 
a few strata of the black variety at the Falls des Chat, on the 
Ottawa. 
The other class is small, angular and ragged. They are 
most frequent on the beaches, whither they are driven by 
waves. 
A curious fact is presented by many parts of Lake Huron, 
and very strikingly in the north channel to St. Mary’s. It 
shews that the debris of the present day is nearly stationary- 
The containing shores of this channel are of different forma- 
tions, the one veing of limestone and the other of green- 
stone; each shore is lined with its own debris, and without 
admixture. A few well rolled granites, puddingstones and 
an | i greenstone do however occur among the cal- 
careous matter. 
In the spring the ice occasionally removes fragments of 
eat size. During the winter it surrounds those which are 
placed in the shallows, and on being broken up in April by 
mild weather, and a casual rise of water,* it carries them to 
some other shore. Remarkable instances of this are found 
on the islets near the south end of St. Joseph, where a few 
yards from the water and little above its level, are deposit- 
ed rolled stones some yards in diameter, with a furrow eX- 
tending from them to the water, most probably tracing the 
last steps of the route to their place of rest. 
- (Changes in the form of the bed of the lake indicate very 
strongly changes also in the nature and quantity of its water- 
* This is very commonly ob ind’s blowing from 
ac ring Se only observed on the wind’s blowing a few days 3 
