DATES OF EARLY AND LATE FROSTS. Table showing the date of the earliest and latest frosts and ice; also the time of disappearance, and depth of frost, and thickness of the ice at Iowa City, from 1839 to 1873, prepared by H. W. Fyffe. 1855 May.... .6 Sept....27 1856 April....19 Sept.... 24 April ... .... ... ... .... ... .... .... .... 3 17 19 16 79865849 March. .25 Nov... 7 .... ... . .... .... .... 18 14 1 13 Sept....26 May ..1 Oct. .15 .2 May. .. 2 Oct.... 15 .10 29 April 19 Sept.. 1857 May.. 20 Oct 10 May. 514 May.. 12 Oct 1858 April....26 Sept. 12 April.... 112 April. 112 April... 16 Oct... 1859 April....23 Sept ...2 April.... 111 April ... 23 Oct 1860 May... 1 Sept. 11 March.. 2011 April.... 2 Oct 1861 May......4 Oct.... 23 March..12 20 April... 16 Sept 1862 April... 24 Oct.... 10 April.... 120 April.... 6 Oct 1863 August..25 August..29 April.... 218 April 8 Oct 1864 March.. 11 Sept....19 April... 17 18 April... 14 Oct 1865 May....11 Oct ...2 April 10 20 April.... 6 Oct. 1866 May. .2 Sept 21 May. .720 April.... 6 Oct 1867 May ...6 Oct 23 May.. 23 18 April.... 6 Nov..... 1868 April....5 Sept....17 15 20 April.... 8 Nov... 1869 May....19 Sept 26 April 721 April... 13 Oct 24 27 2012 .7 10 6 10 24 11 24 21 .... 25 20 7 20 18 20 15 18 31 24 4 18 122 13 20 24 17 21 .... .... 1870 April... 16 Oct 12 April 2018 May 4 Sept.. 1871 May....10 Sept. 21 May 11.. May.... 11 Sept. 1872 April.. .22 Sept .26 April... 22.. April. 22 Sept 1873 April...25 Sept..... 8 April . . . 22│.. April ... 25 Sept.. ... ... 26 30 CHAPTER IX.-PART 2. GEOLOGY. Two State Geologists.-U. S. Geologist at Iowa City.-Prof. Agassiz at Iowa City.-Prof Calvin's List of Fossils of Johnson County. Hall's reports Iowa has had two State Geologists, Hall and White. were published in two volumes in 1858. His work was entirely in the eastern half of the State, and gave a fly-brush touch on Johnson county, while Dr. White's work was entirely in the western half of the State, and did not touch Johnson county at all. So out of four volumes of official State reports on the Geology of Iowa, here is all we find about this county: On the Iowa river, in Johnson county, the rocks are well exposed in the neighborhood of Iowa City, where there are numerous quarries, which have been opened to supply the town with lime and building materials. The layers are of very various lithological character. In a quarry opened about a mile above the city, on the east side of the river, nearly opposite the mill, there is an exposure of about forty feet of a thin-bedded, bluish limestone, which weathers of a dirty yellow. This The layers dip about 5 degrees in a direction S. 80 degrees E. rock is not durable enough to make a good building stone when it is to be exposed to the weather; it will answer very well for underpinning. Nearer the town, on both sides of the river, the rock along the base of the bluffs is a dark-colored argillaceous limestone, which is crowded with fossils, especially corals, among which the genera Favosites, Lithostrotion,* and Stromatopora are the most frequent. Higher up, the rock becomes more compact and less distinctly stratified. It is almost a pure carbonate of lime, containing hardly more than one per cent of other substances. It forms a durable building stone, although not splitting or dressing handsomely. When polished, the large coraline masses which it contains, especially the Lithostrotion*, are very beautiful, and pieces have been worked up into small ornaments, such as paper-weights, and are well known under the name of "Iowa marble." Unfortunately the layers are not sufficiently free from flaws to be manufactured into objects of any considerable size. The same rocks may be observed at various points up the Iowa for a distance of ten or twelve miles from Iowa City. Within the limits of Johnson and Iowa counties we have not been able to find any other outcrop of the Hamilton rocks, than those on the Iowa river along this part of its course. Beyond T. 81, R. 7, there are no rocks seen in place, except a few patches of sandstone, until we reach Tama county. Not a single exposure of rock was discovered on any of the smaller streams to the south of the Iowa, although diligent search was made along the valleys of Old Man's creek, and the north fork of the English river. Through Iowa county low bluffs border the river at a distance of from half a mile to a mile from the stream, but they are made up of finely comminuted materials without even so much as a loose *This is a mistake. Later authorities say that the genus Lithostrotion is not found here, but that the genera Acervularia and Philipsastrea were mistaken for Lithostrotion by Prof. Owen, U. S. geologist, here in 1849, and again by Prof. Hall in 1857-58. [See Prof. Calvin's list of Johnson county fossils further on.] slab or fragment of rock to indicate the character of the underlying strata. Although it would appear from the general direction of the lines of outcrop in this region, so far as they can be ascertained, that rocks of Hamilton age predominate over the large surface in Iowa and Benton counties, over which no exposures of the strata are visible, still there is good reason to believe that there may be considerable patches of carboniferous strata existing beneath the superficial covering of detritus. These may be either the remains of a deposit once spread continuously over a large extent of surface, or more probably, limited deposits in pre-existing depressions of the Hamilton strata. Near Iowa City, on the left bank of the river, is one of these limited patches of rock belonging to the coal measures, which appears to have been a deposit over a very small space, perhaps in a trough-shaped depression or cavity of the limestone. The horizontal extension of the beds which belong to the coal measures is very limited, and from their position would appear that they must have originally occupied a pre-existing depression in the limestone. There are also considerable patches of sandstone, which appear to belong to the coal measures on the Iowa, near the line between Iowa and Johnson counties, forming low bluffs, but not accompanied, as far as has yet been ascertained, by any coal or Coal-measure fossils, by which it might be possibly assigned to this place in the series. That these patches are isolated, and not continuous with the strata of the same age farther west, on the borders of Powesheik and Jasper counties, the nearest point where the Coal-measures are positively known to exist, cannot be positively affirmed, but is rendered probable by the occurrence of the carboniferous limestone farther up the Iowa, in Tama county. At all events, there is little encouragement for explorations for coal in the region in question; as even if small deposits of it should be met with, they are hardly likely to be of sufficient extent or of a good enough quality to be profitably worked. UNITED STATES GEOLOGICAL SURVEYORS IN JOHNSON COUNTY. In 1839 David Dale Owen, of New Harmony, Indiana, was appointed to the then new and by many ridiculed position of United States Geologist, under authority of the land office. He had served the State of Indiana as state geologist, by appointment of the legislature in 1837; and he was the first man who ever engaged in that sort of work as a specialty under authority of the Federal government, although Major Long as early as 1823, and Lewis and Clark still earlier, and other general explorers, had made some casual observations in accordance with the very meager knowledge of geology then in vogue. In 1839 Prof. Owen surveyed the Mineral Point District of Wisconsin and the Dubuque District of Iowa. The grand object aimed at by the Federal authorities in authorizing the appointment of a national geologist was to determine the limits and boundaries and specific locations and probable value of certain mineral lands, such as of lead, copper, iron, coal, etc.. in the then western wilds, which were still more or less in possession of Indian tribes. During his labors in the great lead district of Mineral Point, Wis., Galena, Ill., and Dubuque, Iowa, in 1839, he made a short visit to Iowa City, being here in September or October of that year. One of his assistants was John Brophy of Clinton, who was afterwards a member of the legislature, but finally went to California. They spent about two weeks in Johnson county, and it is remembered that Mr. Brophy swapped horses with Philip Clark. This horse-trade interested the settlers a good deal more than the mysterious business of measuring and squinting at rocks; but after all, they don't remember which man "got the tail end" of that horse trade. Prof. Owen came here again in 1849. Col. Trowbridge was then keeping a drug store, with other goods besides, and Dr. Morsman had his medical office in a room at the back end of the store. Prof. Owen arranged to occupy this room as his headquarters, and it was so used in June, July, August and September of that year. The geological party were constantly making expeditions up and down the Iowa river and its most important tributaries, including Cedar river. Hon. Geo. Paul of Clear Creek township, who was then a young man, made a trip with Prof. Owen in a canoe, from Marengo down to Iowa City. Their field instruments not in use were kept stored here; and here was written some of that masterful report which was published in 1852, a perpetual monument to the conscientious thoroughness, the clear, deep and broad scientific attainments, the plain, terse literary vigor and the artistic skill of that first United States Geologist. This publication covered Owen's entire fieldwork during the years 1847-'48-'49-'50, and Iowa City and Johnson county thus claim a share both in the subject matter and in the writing of it. May 17th of that year (1849) one of his men named Gobert died of cholera, at Muscatine. One of the assistant geologists at that time was B. C. Macy, cousin to Prof. James S. Macy, now of Iowa College at Grinnell, and likewise to Prof. W. P. Macy, now of Drake University at Des Moines. They gathered in great loads of rocks, and when they went away they carried off many boxes of fossils, minerals, soils, plants for further analysis, microscopic examination, determination of species, etc. Prof. Owen's Report was published in a large quarto volume, by Lippincott, Grambo & Co., of Philadelphia, in 1852. It was a grand symposium of scientific zeal, devotion and skill, which has scarcely been excelled even for accuracy of knowledge or correctness of theory by any of our later explorers; and it was elaborately and beautifully illustrated. From this noble work, commencing at its 84th page, we quote all that was said of Iowa City and vicinity and also of the Iowa river country, by this first live geologist who ever gauged Johnson county's place in the geological scale. But first we present a "Chart" which will greatly aid the reader in understanding what is meant by the geological scale, and the relative place in that scale of the different "ages" of the earth as classified and named by geologists: GEOLOGICAL CHART; Compiled Including the Rock Scale of Geological Periods and the "Zoic Calendar of Creation." from the works of Agassiz, Lyell, Huxley, Hæckel, Dana, LeConte, and other first rank authorities in Science at the present time. By HIRAM A. REID, Secretary State Academy of Sciences at Des Moines, Iows. [Published by permission of the Author.] EXPLANATION.-The side line at the left shows what portions of geological time are comprehended In the terms "eozoic," "paleozoic," etc. The first column shows the periods or "Ages" of geological time during which the different successive types of animai life predominated, or were the highest types then in existence. And these two divisions form the "Zoic Calendar of Creation." The second column shows the great general groupings of rock strata,in which are found the fossil remains of the corresponding animal types named in the first column. But, at the "Age of Reptiles" occurs a grand divergement, for it was during this age that animal life pushed out into its most wonderful developments; and there came into existence strange ( and marvelous forms of swimming reptiles, four-footed and two-footed walking reptiles, and two-footed and four-footed flying reptiles. Here also the true birds began to appear, though with reptilian peculiarities; and likewise the marsupial animals, which are a transitional type, between reptiles that produce their young by laying eggs and the true mammals, that bring forth their young well matured and then suckle them. The third column shows the les ser groupings of rock beds as clas-A sified by our American geologists; but many minor subdivisions and local groups are omitted for want H of space. At the top of this column are shown the geological periods of first appearance of races of man, so far as now authenticated by competent scientific au- H thorities. 0 The fourth column shows the N number of feet in thickness of the different groups of rock layers as O indicated by the braces. This Chart is the most comprehensive and thorough in its de- H tails, and yet the most systematically and graphically presented to the eye, of anything in its line that has ever yet been published. Here is the whole story of geology and the ascent of life condensed into the space of a few inches, yet so plainly set forth as to readily fix itself in the memory like an outline map. Scientific terms in newspapers and magazines often catch the reader at a disadvantage; but a reference to this chart will at once show the relative place or period in creational progress to which the best U authorized geological terms apply. It reaches, like a Jacob's ladder, from the lowest inklings to the highest ideals of life on the earth, as taught by modern science and the Christian Bible. |