'20i Mr. Schoolcraft on the ' "'- - 



2iiay be thought important to the statesman, and less tha^ 

 will we considered satisfactory to the professed geologist 

 and scientific amateur. A few marginal notes have there- 

 fore been added, but I have been studious not to overload 

 the original MSS. in that way. 1 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. 



With great respect, and regard, 

 your most obedient servant, 



HENRY R. SCHOOLCRAFT„ 



^'Vernon, Onnda Co. (JV. Y.) JVov.Gth, 1820. 



^* Hon. John C. Cal.houn, Secretary at War^ 



Sir, 



"I have now the honor to submit to you such observa- 

 tions as have occurred to me, during the recent expedition 

 under Gov, 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 

 calcareous strata of secondary rocks are succeeded by a 

 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- 

 heaved masses of granite and hornblende, which appear in 

 elevated banks on the margin of the lake between Dead riv- 

 er and Presque Isle, and from the Porcupine mountains ten 



