STRUCTURAL GEOLOGY.

LAGONDA SANDSTONES AND SHALES ANDMORE LIMESTONE........... BEVIER

about 11 feet per mile. Beyond this the southwestward inclination is resumed to Thomas Hill, where he same seam is found 165 feet below its outcrop on Beecher creek, showing a descent of about 18 feet per mile.1 This structural characteristic is well exhibited in the section, from northeast to southwest, of the preceding page.

The general westward inclination of the strata would carry the Lower Coal Measures below the Chariton river bottoms, and the reappearance of the Lagonda sandstones and shales there is to be attributed to the College Mound flexure.

A similar reversal of dip has been recognized by Broadhead in Linn county, joining Macon on the west, and is described as follows:2 "Along the eastern line of the county the dip is northward from the Hannibal & St. Joe railway to New Boston, the depression amounting to 170 feet as referred to the stream. The true dip may be about 60 feet in that distance, or 5 feet per mile." As the fall of the river is only about 4 feet per mile, it is probable that the dip has been underestimated and should be considered nearer 10 feet per mile. South of the railroad a southward and westward dip is recognized, showing that an axis bearing northwest comes in somewhere in the vicinity of Bucklin. This is in a nearly direct line with the College Mound axis, and is doubtless an extension of. the same fold. The outcrop of coal along the line of this fold in Macon county shows more or less irregularity, due probably to the disturbance attending its upheaval.

The sandstones and shales separating the Macon City and Bevier coals increase in thickness toward the west and southwest. This deposit, however, is subject to considerable variation both in character and thickness.

ECONOMIC GEOLOGY.

In the Bevier area, coal is the only mineral of great economic importance. In the eastern half of the district its production constitutes the leading industry, while the western half is given over almost entirely to agriculture. Building stones, clays and shales are of comparatively small importance as thus far determined.

1 Owing to the small vertical scale used on the general section sheet, this structural characteristic is scarcely apparent.

2 Report Geological Survey 1873-1874, p. 260.

COAL.

Five coal seams have been recognized within the Bevier area, four of which are coextensive with the limits of the sheet except as affected by erosion, as previously explained. All of these partake more or less of the undulations affecting the rocks of the region. Of these four seams, two only-the Bevier and Macon City beds-are susceptible of profitable working. The latter, however, is not of sufficient thickness to give it, at present, commercial importance in competition with the Bevier bed, which furnishes all of the coal now marketed from this district.

THE BEVIER BED.

The Bevier coal is by far the most important coal bed in the district, if not in the State, though it is not yet recognized as having so wide a geographic distribution as do some of the seams higher in the series. It is named from the town where it has been mined extensively for years, and which continues to be one of the chief coal mining towns of the State. This bed is also worked on an extensive scale at Ardmore, by the Kansas & Texas Coal Company. It is also mined for local use at various points within the area east of Middle fork. West of Middle fork we have no data upon which to base an opinion as to the presence and thickness of this bed, except that in a shaft put down in 1872, at New Cambria, just beyond the northwestern corner of the sheet, it is reported absent. A record of that shaft given from memory by Mr. John O. Jones shows 2 feet of coal at about 196 feet from the surface, and 72 feet below this is another bed 12 inches thick, while 40 feet still lower a seam 4 inches thick on one side but thinning out at the other was encountered. The altitude at the top of the shaft is about 810 feet A. T. This shows the upper coal to be, doubtless, the same as that exposed in the slopes north of Hammack's mill, which we have correlated with the Macon City bed. (See p. 18.) Whether the bed 72 feet below this may be considered the equivalent of the Bevier, or whether the latter is absent or has been cut out here by a roll of the overlying sandstones and shales, we are unable to say from the data at hand.

The latter may be the true explanation, though the westward thickening of the Lagonda sandstones and shales might be considered an argument in favor of the former. At Lingo the bed, which is considered the equivalent of the Bevier coal, is found at 124 feet from the surface with 52 feet of shales and sandstones, but no coal, above. This would seem to indicate a like extensive deposit above the Bevier coal, with a rise, and the overlying strata removed by erosion previous to the deposit of the drift mantle, which is here 65 feet thick. The same deposit is 70 feet thick at New Cambria. A complete section of the New Cambria shaft would aid materially in the settlement of this question.

From what has been said it will appear that the presence or absence of coal in paying quantities in the portion of the sheet lying between Middle fork and Chariton rivers cannot be positively affirmed; we venture the opinion, however, that, in the lower two-thirds of this area, it may be looked for with aome confidence. Concerning the region north of Kaseyville considerable uncertainty exists as to what extent the seam has suffered by elevation and erosion beneath the drift. (See p. 44.)

The sections of the preceding pages describe the most important exposures of this bed. Its limits in the eastern portion are clearly defined upon the map, and along this strip indications of its presence are numerous. The bed thins out east of the sheet, though its eastern limit has not been defined as yet. It is frequently diminished in thickness by "horsebacks," or rolls of the overlying sandstones and shales. In some cases the descent of the roof cuts out the coal entirely, but it is soon found setting in again farther on. In some places the sandstone furnishes a good roof, but, owing to its frequent transitions to a shaly character, it is more or less treacherous and requires considerable propping.

Detailed Sections.-The following sections will show the detailed character of the bed where studied:

Section XXVI (E of Section sheet).

DETAILED SECTION OF BEVIER COAL AT EUREKA SHAFT.

Altitude at base of coal about 724 feet, A. T. Distance from surface 75 feet.

1. Limestone, hard, compact...

2. Shale, or clay, drab

FT. IN.

2

4

Section XXVII (F of Section sheet).

DETAILED SECTION OF BEVIER COAL AT SHAFT No. 42, K. & T. COAL Co. (From measurements of A. Winslow.)

Altitude at base of coul about 727 ft. A. T. Distance from surface 118 ft.

The presence of a sandstone below the coal is exceptional, this being the only case in which it has been recognized at this horizon.

A sample of coal from this shaft was collected by Mr. Winslow from part of a freshly loaded market-car. The following are the results of analysis:

ANALYSIS OF BEVIER COAL SHAFT NO. 42, K. & T. COAL CO. AT BEVIER. (Anal. No. 329, Mo Geol. Sur., J. D. Robertson Anal.)

LABORATORY NOTES: The specimens of coal have a bright bituminous lustre with streaks of bitumen; they contain selenite, little pyrite, but much melanterite. red color. The coal coked in the porcelain weak and almost lustreless.

much calcite, little or no The ash is of a dark, brickcrucible, but the coke was