Transactions of the Wisconsin Academy of Sciences, Arts and Letters
volume V (1877-1881)
Buel, Ira M.
The corals of Delafield, pp. 185-193 PDF (2.5 MB)
Pie Corals of Delafeld. 185 THE CORALS OF DELAFIELD. BY IRA M. BUEL. The large collection of fossils made by the Geological Survey at Roberts' quarry, Delafield, Wisconsin, is surpassed in interest and scientific value by no other representation of Palaeozoiu fauna ever obtained from our state. It contains thousands of specimens almost perfectly preserved by the blue friable shale in which they were imbedded; and of the seventy species already distinguished, about one-half are new to science. The coralline representatives found here are of special interest to the student and naturalist. The locality in question (Sec. 2t, T. 7, 1R. 18 W.) lies on the southern shore of Pewaukee lake, and in the edge of a trough carved by glacial forces out of the lower layers of the Niagara limestone, and the soft underlying Cincinnati shales; the basin being occupied in part by the lake itself. By the removal of the limestone layers in the quarry, quite a surface of this shale was exposed, and as this formation somewhat resembles some of the Carboniferous shales, it was supposed by some inquiring mind to belong to that formation. A shaft was accordingly sunk at this point for the discovery of coal, and was not abandoned until a depth of fifty feet had been reached. The mound of rock and clay thrown out of this pit or shaft, the rain-washed monument of a geological delusion, was the source of all of the specimens ob- tained from that locality. These corialline forms are all of small size, the smallest species measuring about an inch in length and about a tenth of an inch in diameter. The largest coral fragment is about two inches in diameter and consists of a sort of central base from which a num- ber of slender arms branched out. Within these limits we find almost every possible variation in form, manner of growth, branch- ing and surface markings. The size, form and arrangement of cells and cell walls, are the principal distinguishing features of these corals ; and as these feat- ures are mainly microscopic, the labor of identification of species and varieties among these thousands of specimens was not a small
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