*F202 Mr. Schootcrajt on the 
may be thought important to the statesman, and less than 
will we considered satisfactory to the professed geologist 
and scientific amateur. ew marginal notes have there- 
* fore been added, but I have been studious not to overload 
the original MSS. in that way. I do not send the views 
and geological charts accompanying the report to Mr. Cal- 
houn, as it would be very inconvenient at the present period 
to copy them, and as the subject may be sufficiently under- 
stood without these embellishments. 
With respect to the deductions, so far as science is con- 
cerned, it is hoped they will be read with candour, and I 
therefore submit them to your judgment and to that of the 
scientific public. 
ith great respect, and regard, 
your most obedient servant, 
HENRY R. SCHOOLCRAFT. 
ce Vernon, Oneida Co. (.N. Y.) Nov. 6th, 1820. 
seat Joun C. Canon, Scoretary at War, 
“IT have now the honor to submit to you such observa- 
tions as have occurred to me, during the recent expedition 
under Goy. Cass, in relation to the Copper Mines of Lake 
Superior; reserving as the subject of a future communica- 
tion, the facts I have collected on the mineralogy of the 
country explored generally. 
The first striking change in the mineral aspect of the 
country north of Lake Huron, is presented near the head of 
the Island of St. Joseph in the river St. Mary, where the 
caleareous strata of secondary rocks are succeeded by 2 
formation of red sand-stone, which extends northward to 
the head of that river at Point Iroquois, producing the falls 
called the Sault de St. Marie fifteen miles below, and thence 
stretching northwest along the whole southern shore of Lake 
Superior to the Fond du Lac, and into the regions beyond 
This extensive stratum is perforated at various points by up- 
ved masses of granite and hornblende, which appear 12 
elevated banks on the margin of the lake between Dead riv- 
er and Presque Isle, and from the Porcupine mountains ten 
