The history of Columbia County, Wisconsin, containing an account of its settlement, growth, development and resources; an extensive and minute sketch of its cities, towns and villages--their improvements, industries, manufactories, churches, schools and societies; its war record, biographical sketches, portraits of prominent men and early settlers; the whole preceded by a history of Wisconsin, statistics of the state, and an abstract of its laws and constitution and of the constitution of the United States
Chamberlin, T. C.
Topography and geology, pp. -120 PDF (5.3 MB)
HISTORY OF WISCONSIN. was no crumpling or metamorphism of the strata, and they have remained to the present day very much as they were originally deposited, save a slight arching upward in the central portion of the state. The beds have been somewhat compacted by the pressure of superin- cumbent strata and solidified by the cementing action of calcareous and ferruginous waters, and by their own coherence, but the original character of the formation, as a great sand-bed, has not been obliterated. It still bears the ripple-marks, cross-lamination, worm-burrows, and similar markings that characterize a sandy beach. Its thickness is very irregular, owing to the uneven- ness of its Archaean bottom, and may be said to range from rooo-feet downward. The strata slope gently away from the Archaean core of the state and underlie all the later formations, and may be reached at any point in southern Wisconsin by penetrating to a sufficient depth, which can be calculated with an approximate correctness. As it is a water-bearing formation, and the source of fine Artesian wells, this is a fact of much importance. The interbedded layers of lime- stone and shale, by supplying impervious strata, very much enhance its value as a source of fountains. LOWER MAGNESIAN LIMESTONE. During the previous period, the accumulation of sandstone gave place for a time to the formation of limestone, and afterward the deposit of sandstone was resumed. At its close, with- out any very marked disturbance of existing conditions, the formation of limestone was resumed, and p-rogressed with little interruption till a thickness ranging from 50 to 250 feet was attained. This variation is due mainly to irregularities of the upper surface of the formation, which is undulating, and in some localities, may appropriately be termed billowy, the surface rising and falling ioo feet, in some cases; within a short distance.' This, and the preceding similar deposit, have been spoken of as limestones simply, but they are really dolomites, or magnesian limestones, since they contain a large proportion of carbonate of magnesia. This rock also contains a notable quantity of silica, which occurs disseminated through the mass of the rock; or, variously, as nodules or masses of chert; as crystals of quartz, filling or lining drusy cavities, forming beautiful miniature grottos; as the nucleus of otilitic concretions, or as sand. Some argillaceous matter also enters into its composition, and small quantities of the ores of iron, lead and copper, are sometimes found, but they give little promise of value. The evidences of life are very scanty., Some sea-weeds, a few mollusks, and an occasional indication of other forms of life embrace the known list, except at a few favored localities where a somewhat ampler fauna is found. But it is not, therefore, safe to assume the absence of life in the depositing seas, for it is certain that most limestone has orignated from the remains of animals and plants that secrete calcareous material, and it is most consistent to believe that such was the case in the present instance, and that the distinct traces of life were mostly obliterated. This formation occupies an irregular belt skirting the Potsdam area. It was, doubtless, originally a somewhat uniform band swinging around the nucleus of the state already formed, but it has since been eroded by streams to its present jagged outline. ST. PETER'S SANDSTONE. At the close of this limestone-making period, there appears to have been an interval of which we have no record, and the next chapter of the history introduces us to another era of sand accumulation. The work began by the leveling up of the inequalities of the surface of the Lower Magnesian limestone, and it ceased before that was entirely accomplished in all parts of the State, for a few prominences were left projecting through the sand deposits. The material laid down consisted of a silicious sand, of uniform, well-rounded-doubtless well-rolled-grains. This was evidently deposited horizontally upon the uneven limestone surface, and so rests in a sense 116
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