Box 12, Folder 12: Archaeology

1 [187-?]

Having been requested, by Dr. J. W.Foster of Chicago, to furnish him such items as have been found in Wisconsin, relating to that ancient people who once inhabited this country, of whom nothing is now known except what can be gleaned from the study of the remains of their industry; and wishing to contributed whatever I can to preserve a record of all important discoveries of this kind, I have prepared the following paper, which may be entitled

Some Items of the Antiquities of Wisconsin.

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Some Items of the Antiquities of Wisconsin

By I. A. Lapham.

In the eastern part of Walworth, one of the southern border counties of the state of Wisconsin, is a limited region of country which is found to possess much interest both for the Geologist and the Antiquary. The ground is quite undulating, as is common in the regions where the underlying rocks are deeply covered with those loose materials consisting of clay, sand, and gravel with occasional boulders usually called drift, and whose Origin is now generally attributed to the agency of the glaciers of the "ice period". Bordering the region spoken of, are more considerable hills of coarse material, in which are found those singular hemispherical depressions known as "Potash Kettles". Below the surface soil in this district we find a yellowish clay, sparsely interspersed with fine gravel, and with a slight admixture of sand.

The pebbles consist of the usual variety, including granite and other azoic rocks of Northern Origin,

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associated with limestone, bituminous shale and flint from nearer (but still northern) localities. This uniformity of texture; the fineness of the gravel interspersed through it; and the absence of large boulders, indicate a modified drift, or glacial = drift that has been worked over and re = deposited by the action of water; very much after the manner in which Lake Michigan is now wearing down and re= arranging the steep banks along its western shore. It is clearly a lacustrine deposit.

It is important for us to know when this change in the disposition of the drift material of Walworth County was accomplished; and although the question cannot be answered with certainty, there are some facts which shed some light upon the subject. The modifying influence of water, it is obvious, must have commenced very soon after the close of the ice period, which may have been 200,000 years ago - more or less - and it has continued down to the present day. But whenever this yellow clay is found in connection with other any materials, it is always the uppermost;

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thus showing that it is a later formation.

The well diggers of Walworth county may supply some facts of importance in this connection; they tell us that at a depth varying from a few feet to sixty, they come to the bottom of this yellowish modified drift clay, and that immediately under it, is often found remains of a blach soil quite similar to that which is now found at the surface; often also beds of peat, overlying marl, beneath which is a very hard tough clay of a reddish color, with pebbles and bouldesrs [boulders]

It was my good fortune in 1850 to see one of these wells very soon after it was dug, and to learn the details of the several strata penetrated, preserving specimens of the interesting things brought to light. The yellow clay was here eighteen feet in depth, resting upon a bed of soft fine blue clay a foot and a half thick in which were found small logs of white cedar (Thuja occidentalis). This wood is well preserved; is not in any sense petrified, or changed to stone; but it is incrusted and interpenetrated with sulphuret of iron in minute shining crystals.

The annual rings of growth are very thin and numerous, indicating a slow growth; and that

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the climate, when this wood was a living tree, was less favorable to vegetation than that which now obtains in the same region.

The next layers penetrated were a black and a yellowish soil, doubtless the same in which the trees found support. The black soil had the charascteristics [characteristics] of peat.

Then was found another foot and a half of white shell marl, just such as is now being formed at the bottom of many of our small lakes; and from this marl I collected a number of fresh water shells, all of kinds now living, belonging to the genera Paludina, Planorbis, Physa, Amnicola + Valvata.

A layer of sand two feet thick separated this marl from the hard reddish clay, the unaltered glacial=drift, into which the well was sunk twenty four feet (fifty in all) without reaching the underlying rock.

Other wells in this region have been sunk 120 feet without finding the bottom of the drift; and as there were probably not dug from the highest places we may assume the whole thickness of all of these loose surface deposits to be two hundred feet or more.