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         No thorough geological survey of the county has ever been made, continues Judge Tuthill. In the Spring of 1849, David Dale Owen and his party made a somewhat hasty examination of several localities. In his report, he says:

         On Section 27, Town 79, Range 2, on the east bank of Sugar Creek, ledges of rugged magnesian limestone rise twelve feet above the water level, at the foot of a dam. In this rock I found no well-defined fossils, but the imperfect Terebratuloe and Pentameri, as well as the lithological character, leave little doubt that it belongs to the Upper Silurian epoch. This inference was confirmed by observation on the opposite side of the same stream, where these magnesian beds are at an elevation of from fifteen to twenty feet, and have resting on them from fifteen to twenty feet of a white, brecciated, close-texture limestone, similar to the beds of the Upper or Rock Island Rapids of the Mississippi River.

         In juxtaposition with these calcareous beds, in a hollow, not thirty paces from the creek, and at an elevation of twenty-five feet above it, a light, buff, banded freestone, an outlier of the coal formation, crops out.

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         On Section 14, Town 79, Range 2, on the same creek, are solid ledges of magnesian limestone, to the height of thirty feet. At this locality, no white limestone was observed overlying it; only some loose pieces of freestone are scattered on the slopes. In some of the slabs of magnesian limestone lying in the quarry are casts of Cyathophylloe, a small Terebratula and an Orthis, not sufficiently well preserved to make out the species.

         At the mill on Rock Creek, in Section 14, Town 80, Range 3 (now known as the stone mill), is a similar rock, having, however, a more earthy and arenaceous appearance, and sometimes banded. There, the white, brecciated limestone lies about twenty feet above the water.

         On Cedar River, half a mile from Rochester, is magnesian limestone like that at Parkhurst, and a variety of freestone is again in close proximity; and half a mile west of the same place, twenty feet of buff-colored, earthy, magnesian limestone is exposed, with nests of calcareous spar and black spots disseminated, such as are found at the head of the Upper Rapids.

         On Rocky Creek, Section 30, Town 80, Range 3, a light-colored magnesian limestone is in place; and the same rocks form ledges of thirty-five feet above the level of Rock Run, on Section 27, Town 80, Range 3. At these latter localities, the magnesian limestone is of a much lighter color than usual; it has, however, the texture and glistening aspect peculiar to the dolomite rocks. Only obscure casts of organic remains are found in it.

         In digging a well on Section 9, Town 80, Range 3 (on the John Huber place), rock was struck at thirty-two feet and the excavation continued for forty-three feet more; first, through white, close-grained limestone, and then magnesian limestone. The top of the well is about seventy feet above the waters of the Cedar. A mile or a mile and a half from this place, on Rock Run, earthy magnesian limestone, with dark specks, is exposed, eight feet above the water.

         South of Mason’s Grove, porphyritic boulders are scattered over the prairie, of a similar composition to those observed in the Winnebago Reserve, but smaller, about one third the size.

         At the crossing of Clear Creek, on Section 29, town 82, Range 4, twenty-six feet of buff-colored magnesian limestone, with cavities, is exposed, in a quarry. The lower strata, to the height of fifteen feet, lie in heavy beds, from one and a half to three feet thick. The next foot is composed of layers, of from one to three inches thick; and over the whole, the beds are much broken and irregularly divided.

         In the bed of Cedar River, in Township 80 north, Range 3 west, probably on Sections 34 and 27, limestone, possessing a close, lithographic texture, is found, at a low stage of the river.

         On Section 28, Town 81, Range 4, where the south line of the section strikes the west side of the river, above Washington ferry (now Cedar Bluffs), are ledges of cream-colored limestone, in even, bedded layers, to the height of some thirty-five feet above the river.

         In some of the layers, small hemispherical concretions run in the joints of the strata, as well as through the substance of the rock itself. The best of the slabs approximate in character, although of too course a texture, to lithographic limestone. The lowest layers have very much the aspect of the beds observed on the west side of Clear Creek. A north and south crevice traverses the rock at this place, containing some calcareous spar and ferruginous clay; but no metallic ores have been discovered, the crevice being filled with tumbled wall-rock intermixed with red clay. The strata have a southerly dip of 3°. A corresponding wall of rock is also on the opposite side of the river, which would form solid natural abutments for a bridge.

         A quarter of a mile lower down, near the middle of Section 34 Township 81, Range 4, there is a fine quarry of heavy beds of subcrystalline magnesian limestone. This rock, which is of the Upper Silurian period, dips southwesterly under the thin bedded limestone above the ferry. These latter appear, from their chemical composition, to belong to the Devonian system, although no evidence was derived from organic remains, which are very scarce at both localities. Some well known Devonian forms are however found in the debris of the river near by.

         In Hickory Grove, on the southeast corner of Section 34, Township 81, Range 4, both magnesian limestone and white limestone lie within two yards of each other. The latter containing Spirifer euruteines, Gorgonia retiformis and siromatopora polymorpha.

         The inferences to be deduced from the foregoing observations are, that all the rocks, as well those referable to the Upper Silurian as to the Devonian periods, have been subjected to disturbances subsequent to the carboniferous era. These disturbances have been chiefly dislocations, through which the strata have been displaced more by abrupt vertical depressions and elevations than by prolonged arched waved movements.

         That the subcarboniferous limestone, which forms a zone around the coal measures and occupies the Valley of the Mississippi between latitude 40 degrees and 41degrees is lost to view in Cedar County.

         The calcareous beds, which constitute a conspicuous feature of the lower coal measures of the Des Moines Valley are not traceable here.

         The Devonian rocks consist chiefly of close-textured white or gray limestones, sometimes brecciated, or of argillaceous limestones, both varieties containing a much smaller percentage of magnesia than the adjacent dolomitic rocks of Upper Silurian date. The former are no great thickness, probably not exceeding seventy feet, upon which Judge Tuthill makes the following comment:

          “In the subsequent geological survey of the State, by Professor James Hall, in 1855-56-57, and by Dr. Charles A. White, in 1866 to 1869, Cedar County seems to have been somewhat . . .

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. . . neglected by them; but both agree in the conclusion that some three-fourths of the rock formations of the county are Devonian, of the Hamilton group, thus placing them above and of a later formation than the Upper Silurian, as stated by Prof. Owen.”

         Doctors, we know, will disagree, but in this case the difference of our learned Professors is really unimportant, the Devonian being the geological formation that immediately overlies the Upper Silurian, and, as both are below the carboniferous coal measures, we must in either case give up the idea of finding coal in Cedar County in paying quantities; and it will perhaps be good policy to give up also the dream of native silver, which some of our enthusiastic Rochester* friends have indulged in, for Dr. White says:

          “To most persons, it will doubtless seem superfluous to offer any remarks in relation to silver in Iowa, yet considerable local excitement has been caused by the alleged discovery of silver in Cedar County. These reports were believed in by many to be true, especially when silver or a metallic compound resembling it were shown as the product of the rock reported to contain it.”

         This rock is of the Devonian age, and consists of more or less irregular layers and concretions of carbonate of lime, occasionally having fine crystalline specs of iron pyrites disseminated through it.

         A number of specimens of this rock have been obtained both by personal selection and from persons interested in knowing the facts in the case. These have been carefully analyzed by Prof. Emory, and the result is that no trace of silver has been detected in any instance.

*See chapter devoted to Rochester for a full history of the Rochester silver mining excitement.