Box 15, Folder 6: Geological Survey 1873

Irving's Report - 1873

Ores selected with the greatest care with a view of obtaining a fair average showing what would be the actual furnace product - rather than the amount of iron in a few rich samples. Method of analyses fully explained - Results more valuable than if made from land specimens &c.

Full details of the topographical features of Ashland Co.

Remarks on the climate, soil, timber, and agricultural capabilities -

The determination of the relative ages of the "Iron bearing" and of the "Copper bearing" series of rocks appear to be confirmed by observants made in Ashland & Douglas Counties.

Full details of the geol. structure of the Penokee Iron Range given, showing its relation to the other rocks, the value of the ores &c

Also of the copper bearing series.

South dipping sandstone - has feldspar grains mica Cement of conglomerate trap = sand - pebbles of trap sometimes a foot in diam.

Iron bearing work traced for a distance of 60 miles.

General nature of iron ores given Thickness of ore-bearing beds 500 feet (100 feet of ore) Iron bearing rock 4000 - Depth unknown but must be considerable. 300 feet exposed without variation

[small sketch] Do they wedge out below? Do they curve under Copper-bearing rocks and come up again? & where?

Amount of ore enormous Facilities of quarrying Unusually great Quarrying in open air - not mining Great regularity of beds - no folding - Changes gradual Yield 45 pr ct metallic iron. Remarkably free from phosphorous & sulphur Differs from Marquette ores by carrying magnetite.

Copper bearing rocks including certain conglomerates & highly dipping sandstones are found to be much older than the horizontal (Potsdam) sandstone found along the immediate shores of L. Sup. in Wis. The Iron bearing series, corresponds with those of Marquette & Menomonee are still older - and yet younger than the crystalline granite &c still further south.

2 Irving Report 1873

Gen. Conclusions - [??] - Amt of ore enormous - 400 feet thick unknown depth - (300 ft at gap) 30 miles long! Amt carrying 45 pr ct is very large, at gap & west of it. Banded ore may be separated by hand picking. Contains more magnesia, lime, than Marquelle Ore - & there are [flux??] forming materials; also manganese which gives value to the iron. All these ores are silicas Such ores will make iron of the best quality.

Of course these ores cannot compete with the Marquette Ores which yield 60 pr ct. of iron. Irvings Report covers 275 Ms. pages

It is accompanied by the Report of Ed? T. Sweet on the Copper range in Douglas Co. 143 pages. Length of this range of trap rocks &c. about 30 miles Sandstone [expo???] NE 1/4 27 T48 R 14 W - (Sweet) North [???] 29 - [illegible]

The Sweet reports numerous details concerning the trap ranges; the copper veins; history of mining operations in Douglas Co. and many useful suggestions is to the nature of veins, and where to search for them.

It appears that these trap ranges consist of a series of subordinate ranges having a Direction N E & S. W. - They exist in many varieties of rock, - trap, breccia, &c -