290. J. P. Kimball on Iron Ores of Marquette, Michigan. 
ArT. XXXVI.—On the Iron Ores of Marquette, Michigan; by 
J. P. KimBatu, Ph.D. 
Ir is proposed in the present article to record a few observa- 
tions made, in the month of May last, in the Iron region of 
Marquette county, Michigan, with the view of elucidating cer- 
tain obscure points in the geology of the immense beds of earthy 
red hematite, specular and magnetic iron ores, with which this 
district abounds to an unparalleled extent, constituting it beyond 
any doubt the most opulent source of iron in the world yet dis 
covered. It was not my privilege carefully to explore this re 
gion beyond a limited district near the middle. I am therefore 
unable to add any information as to the geographical extent of 
the iron deposits to the published results of Foster & Whitney's 
survey. Indeed, the following contribution to the knowledge of 
this region is chiefly by way of observation of the instructive 
rock-cuttings in the iron mines, or rather quarries, and in one 
to publish the special report upon the Marquette Iron Region by 
Mr. J. D. Whitney, the results of a second geological ex ge 
In their survey of that portion of the large area of t e Nort 
west exclusively occupied by schistose, metamorphic and bla 
line rocks, which is included in the northern peninsula of Mi ae 
gan, Messrs, Foster & Whitney in 1851 marked out the k 4 
. lines of two distinct systems of crystalline rocks, one of whit 
was defined as metamorphic, their Azoic proper; W! i 
other, distinguished as a great development of gra 
outstretching in separated expanses, was described ; 
name of granite belts or ranges. The relation to each other 
* “ 0 
these two systems was hardly traced to conclusiveness ue Ae 
the concealment of their conditions of contact; but the my 
was assigned to an origin later than the Azoic series UpOl | 
testimony of disturbances of the upper metamorphic strata BY 
intrusive masses of the granite, and earlier than the Silurian, e dis. 
lower beds of the Potsdam sandstone are seen to res 4; ; 
turbed around them.’ The distribution of the Azole 40 gran 
44-48. 
” Report on the Geol. of the Lake Superior Land District, Part Il, 1851, 
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