Box 11, Folder 7, Correspondence July to September 1873

Office of the U.S. Lake Survey Detroit, Mich. July 2d 1873

I.A. Lapham Esq.

Dear Sir:

I hope to be able to determine the present season, latitude of the Wisconsin State Line and the longitude of the 4th Principal Meridian, near Galena Ill. longitude of 4th Principal Meridian near Tomah & latitude of nearest correction line (J. 20): latitude of correction line (J.30): near Stillwater and perhaps near Green Bay: latitude of correctionline(J.20) near Apperton: of Wisconsin State Line near Kenosha.

Very Respty Your Obedt Servt C.B. Comstock Major of Engineers & Bvt. Brig, Genl.

Gen. C.B. Comstock July 2

R.D. Irving Ashland Wisc. July 3rd 73

Dear Sir

Your favor of the 16th ult, reached me last Saturday, the 28th ult. at Odana I return receipt for the amount sent me by draft ($500.00)

We are just in town from our first trip of nearly a month. Our route was along the future railroad line thirty miles to Penokee Gap, stopping some days on the "Granite Range," where the Bad River cuts thro it & where some heavy cutting is being done on the railroad

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line. At the Knopee Gap we made headquarters for nearly two weeks, dividing into parties, after becoming familiar with the structure at the Gap; one party racing the range westward to its termination in Sec 24, 44, 4w, another starting eastward to "The Gorge" of Tyler's Fork, a third remaining at the Gap to make a detailed study at the most important point. The Eastern Party was not successful in reaching the "Gorge," the range being found non continuous in that direction & broken into numerous detached

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masses with intervening swamps. The guides refused to go further. The point reached was in Sec 2—44 2W. About 14 miles or one half the entire length of the Penokee Range, has been carefully examined. It is proposed to cover the remainder by making the Gorge of Tyler's Fork a starting Point & working Eastward and Westward from there.

To the south of the Gap a point in Sec 23 -44 3W has been reached - and a detailed section made from

there at night angles to the strike about one mile in length.

From the Gap our route was back over the Granite Range to the passage of Bad River through it—in Sec 30, 45, 2W— & thence by a circuitous route to the Ashland Mine at the Forks of Bad River and Tyler's Fork - on 17-45-2W. - Here we made our first study of the copper bearing series—We had the greatest difficulty—in reaching this point owing to an unusually large windfall which took place last fall. It entirely surrounds