CHAPTER VII

GEOLOGICAL ASPECT OF THE COUNTY-SOIL OF AMPLE DEPTH AND FERTILE-COAL IN

VAST QUANTITIES ITS ORIGIN-LIST OF MINES OF THE COUNTY-TIMBER— STREAMS AND THEIR NAMES.

The surface of Appanoose county is, generally speaking, a nearly level plain, lying on the water-shed dividing the Mississippi and Missouri rivers. The depressions for the river and creek beds are shallow, and it is probable that the extreme difference between the water-bed of Chariton river and the highest prairie summits will not exceed a hundred and fifty feet. The soil of the county is a brownish-gray loam, largely intermixed with clay, but yet tempered sufficiently with sand to be easily plowed and cultivated. It also absorbs the rainfall rapidly so that very muddy roads are rare. The surface soil is of ample depth and very fertile. The substratum is nearly pure clay, and with proper care any portion of the subsoil of this county can be made into excellent brick. Both Professor White and Mr. St. John visited Appanoose county in 1868, and the former gentleman records that it is now known that all three of the divisions of the coal-measure group occupy the surface beneath the drift; the lower occupying the northwestern portion, the middle traversing it near the center, and the base of the upper appearing as ledges of limestone along Copper creek, west of Centerville. In the valley of that stream, Mr. Talbot had opened a mine in a three-foot vein of good quality. This is regarded as the upper bed of the middle coal-measures, and whatever other beds may exist within the county doubtless belong beneath it. Thus, the place of all the heavy beds of coal found elsewhere is at considerable depth here; but they may be looked for nearer the surface in the northeastern part of the county. It is believed that a shaft sunk in the valley of the Chariton river near Centerville would pass through all there is of the coal-bearing strata within three or four hundred feet. There are good reasons for believing, also, that one or more good beds of coal would be passed through at that or a less depth, besides the one worked by Mr. Talbot.

W. P. Fox, the geological commissioner of Iowa at the Centennial Exhibition, visited Appanoose county in 1875 and made a statement, which is undoubtedly true, that a vein of coal exists beneath the one now being worked, and gave it as his opinion that it lies from thirty-five to fifty feet below the other. There is no reason to disbelieve his statement that the lower vein should be five or six feet in thickness. Mr. Fox claimed that the slate overlying the coal is suitable for roofing purposes, but this was a blunder on his part, and pointed out the immense deposit of potter's and fire-clay overlying the shale.

Mr. Fox also visited the saline springs in the edge of Davis county, and

describes them as being located in an outfield of the Onondaga salt group, which was certainly an egregious blunder on his part, for if that formation exists in lowa at all it must lie at least five hundred feet below the coal beds. The saline character of the Davis county springs is owing undoubtedly to local peculiarities.

After the above paragraph had been written, the compiler had an opportunity to consult Owen's Survey of the Northwest, made in 1849. That distinguished and reliable scientist visited several mineral springs in the eastern part of Davis county, and states, on page 111 of his report, that the chemical analysis showed the water to contain chloride of sodium, chloride of magnesia, bicarbonate of iron, bicarbonate of lime, sulphate of magnesia and sulphate of soda. The salt exists, it is true, but the other minerals mixed with the water would render it worthless as a commercial article. Fox must have been well aware of Owen's visit to this neighborhood, for he was himself an assistant in Professor Whitney's survey ten years later, and his assertion that the springs along Soap creek have any value should be entirely disregarded.

THE ORIGIN OF COAL

It is believed that a further discussion of the topic with reference to the coal mines may not be out of place. This article of commerce is found in various places in the geologic series of formations, beginning with the Middle Carboniferous, in which stratum belong the coal-seams found in this county, and ending with those much more recent in point of time, which are found in the Middle Tertiary. These latter beds are found best exposed in Wyoming and are in all about thirty feet in thickness.

But the coal field in Iowa belongs to the true Carboniferous system of the writers upon the subject, and is, moreover, the outfield of the vast coal basin partly covering this state, Illinois, Indiana, Ohio and Pennsylvania. It is only in the Alleghanies that subterranean action has converted any part of the coal into anthracite. Everywhere else in the immense basin it is strictly bituminous, varying, however, from the article as first prepared by the economic forces of nature from the block coal of Indiana to the cannel coal found in several places in Iowa.

In the ancient history of the earth, the leading events of which have been slowly deciphered through the researches of scientific men, the earth's crust was much more plastic than at present, and the climate was more than tropical from pole to pole. The carbon now stored beneath many feet of soil and rocks was mingled, in the form of carbonic-acid gas, with the atmosphere. The earth's crust lacked the stability it now possesses. A vast plain would gradually thrust itself to the surface of the ocean, where vegetation would at once begin. Great forests would grow in the tropical heat, fanned by the damp sea breezes, and stimulated by the carbon in the atmosphere. This vegetation was usually composed almost entirely of a species of palm and a variety of fern that grew to an enormous size. That this is true cannot be disputed, for in many coal districts the stumps. of immense trees are to be found in the clay underlying the coal, and often the trunks can be found only partially converted into coal. But what is more curious still, is the fact that in Nova Scotia mines, when the vegetable mold that now forms the coal bed was buried up, many trees were left standing. The lower