November 27th.  I determined to spend the winter in New York; to place the agency, in the interim, in charge of an officer of the garrison, and to visit Washington from this city during the season.  Captain N.S.  Clarke, 2d Infantry, consented to perform the duties of the agency during my absence.  And having obtained leave of absence from my superior in the department, I embarked, in September, on board a schooner for Detroit, with Mrs. Schoolcraft, her infant son William Henry, my sister-in-law, Miss Anna Maria Johnston, and a servant, making a little group of five.  We touched at Michilimackinack.

We were kindly received at Detroit by General and Mrs. Cass, who had invited us to be their guests, and pursued our way, without accident, to New York, where we arrived the day prior to the annual celebration of the Evacuation.  New scenes and new situations here rapidly developed themselves.  But before these are named, some letters that followed me from the Lake may be noticed.

B. F. Stickney, Esq., writes (October 15th) from the foot of the Miami of the Lakes (now Toledo):  “Recently I have had brought to me a specimen of manganese, the bed of which is located about nine miles south-west of this.  The quantity is represented to be very extensive.”

I find that strontian is much more extensively interspersed through the rock formations of this region than I had heretofore conceived.  At the foot of the rapids of this river, there are extensive strata of carbonate of lime, sufficiently charged with magnesia to destroy all vegetation, when converted to the state of quicklime; although Dr. Mitchell, in his “Notes to Phillips’ Mineralogy,” denies to magnesian carbonate of lime this quality.  But I have tested it fully.  I rather think the doctor’s mistake must have arisen from a supposition that Mr. Phillips intended to say that the magnesia, when in combination with carbonate of lime, and in situ, was destructive to vegetation.

Ohio and Erie Canal.—­“A commissioner of the State of Ohio, with engineers, is taking levels, examining water-courses, and making estimates of cost, to ascertain the practicability of making a canal from Cincinnati up the valley of the Big Miami, and Loromier’s creek, across the summit level, to the Auglaize and Miami of Lake Erie, to the level of the lake water.  These surveys will give us much assistance in judging of the geological formations between the Lake and the Mississippi.”

Geology.—­“As an outline sketch, I should say that, from the rock basin of the Erie-sea to the Ohio River, by the way of Fort Wayne, there is a ridge, of about 200 feet elevation, of rock formation, all new floetz, with a covering of from ten to seventy feet of pulverulent earth.  At the summit this layer is twenty feet.  That the Miami and Wabash have cut their courses down to the rock, with only here and there a little sand and gravel upon its surface.  As far as conjecture will go, for the levels of the strata on the Wabash and Miami, the same mineralogical characters are to be found in the strata, at the same elevation.  This would be an important fact to be ascertained, by the levels accurately taken.”