7 
254 Geology and Mineralogy of the 
Art. VI.—Geological and Mineralogical Observations on 
the North West Portion of Lake Huron ; by Dr. Joun 
I. Biessy, of the Medical Staff of the British army in 
Canada, and Assistant — under the 6th and 7th. 
Articles of the Treaty of Ghent 
TO THE EDITOR OF THE AMERICAN JOURNAL OF SCIENCE. 
Sir, f 
very respectfully beg your acceptance of a few geolo- 
gical observations on the north west portion of Lake Huron; 
collected mae rather favorable circumstances in the sum- 
mer of 1 
The pa a ee Lake Huron under examination is contained 
within the Latitudes 45° 46’ and 46° 20’; 3; and b the Lon- 
gitudes 83° and 84°, with ‘some exceptions of small im- 
rtance. 
At the upper part of this space the waters of Lake Supe- 
rior are ee through the medium of the straits of St. 
Mary and the minor Lake, George ; and by three channels, 
the sum of whose breadth perhaps does not exceed a mile— 
as the interval of three leagues or more between the north 
and south shores of Lake Huron, is here (lon. 84° lat. 46° 
ond Bs ge a occupied by the large islands of La Crosse 
hag with which we are more immediately con- 
cerned, is compact in shape and woody, rising to the height 
of five hundred feet in the centre. It is about sixty-five 
ree in circumference. Its most southern point is at Fort 
t. Joseph, in the latitude of 46° 5’—six miles north of 
Drummond Island. 
This latter island is the most western of the great Mani- 
touline chain; which in the latitude of 45° 58’, divides the 
Lake into two unequal parts. One extremity approaches 
to within a mile of the South Main, in lon. 83° 52’, and the 
other is contiguous to Cabot’s He: ad. 
_Drummond’s Island is an assemblage of rocks and mo- 
$< Seventeen to twenty miles long, by five in average 
The iene Manitou, mo next presents itself in the line, 
ae ar charac ter, > and is about seven miles in diameter. 
