46 Schoolcraft on ihe Copper of Lake Superior. 
ly carbonic acid and water. It is consequently among the 
number of the ores of this metal that are most profitably 
wrought in the large way. Should you entertain a wish to 
place a portion of the ore transmitted in the hands of a chem- 
ist for the purpose of analysis, I take the liberty to suggest 
that the envelope containing the small granulated masses, 
would probably afford the fairest test. 
t may be pertinent to add to the foregoing remarks, that 
I have succeeded in the course of the present season, in 
procuring from lake Superior, a mass of native copper 
weighing forty-two pounds, which is very pure and mallea- 
, and contains small points of native silver! This mass 
is from the waters of the Ontonnagon, but it is no part of 
the great mass formerly described. 
HENRY R. SCHOOLCRAFT. 
U.S. Indian Agent, resident at St. Mary’s. 
Hon, John C. Calhoun Secretary of War. 
Localities of Minerals. 
_ Sulphate of Strontian—Presque Isle, on the Maumee 
river, Wood C ; Ohio. This locality is the site ‘of 
Wayne’s celebrated victory over the confederated Indians 
in 1794. The Maumee river here washes a rocky shore, 
surmounted by a grove of oaks, with an extensive prairie 
back of it. ‘The crystals of Strontian are plentifully inn- 
bedded in the rocky bank of the river, which is a compact 
limestone, similar, in its characters, to that which pervades 
the shores of lake Erie. It is about 40 miles south of the 
noted locality of this mineral upon “Strontian Island,” ‘and 
indicates how extensively this substance is distributed 
through that section of country. There is nothing peculiar 
in the forms of the crystals found at this place, or other 
characters, unless it is a tendency in the colour of all the 
specimens observed, to assume a full sky blue. Some of 
crystals contain other crystals of calcareous spar im- 
bedded. {{ first visited this locality in July, 1821. I bave 
also in my posession a nodular mass of limestone from the 
north shore of lake Huron, having impressions of the ma- 
spore upon its surface, which, on being broken upon one 
end, disclosed radiated crystals of Sulphate of strontian, 
in connexion with, and shooting into, limpid masses of folia+ 
