Marion county is located in the northeastern part of the state. It has a rolling to hilly topography, the surface being especially rough adjacent to the larger streams. The bluffs along the Mississippi river rise to a height of from 50 to 250 feet. The Chicago, Burlington and Quincy and St. Louis and Hannibal railroads, together with the Mississippi river, provide the eastern portion of the county with good transportation facilities.
The Burlington limestone, which is well exposed along the streams, combined with good transportation facilities, has made this county one of the largest producers of lime. Hannibal is one of the most important lime producing centers in Missouri.
Formations belonging to the Devonian, Mississippian and Pennsylvanian series underlie the county. They contain both limestone and shale chemically suitable for the manufacture of both lime and Portland cement.
The Pennsylvanian strata underlie a comparatively small area in the southwestern comer of the county, although small outliers occur throughout the remainder of the county. The stone is mainly sandstone and shale. The latter is not sufficiently extensive to be of value as a cement making material.
The Burlington limestone, which underlies a greater portion of the county, is from the standpoint of the lime and cement industry, the most valuable within the area.
This formation has a maximum thickness of 150 feet. It consists of brown to gray, fossiliferous, coarsely crystalline limestone, containing rounded nodules and layers of white chert. The chert is most abundant in the upper part of the formation, where it often constitutes one-fourth of the total mass. This part of the formation also contains a large percentage of buff colored limestone, which is ordinarily somewhat magnesian in character. The lowest 40 feet of limestone has a light gray to white color and contains less chert. This portion of the formation is used exclusively in the manufacture of lime.
The Keokuk formation overlies the Burlington in the northern part of the county. It is well exposed along Troublesome creek, where it has a thickness of approximately 70 feet. It consists mainly of fine grained, bluish gray limestone, interstratified with thin beds of bluish shale. Geodes of chert are very abundant in some beds.
Beneath the Burlington occurs a ledge of Chouteau limestone. It has a maximum thickness of 40 feet, of which seldom more than 25 feet are exposed.
The Vermicular sandstone and shale known as the Hannibal, underlie the Chouteau. The upper beds are sandstone, which gradually pass over into shale below. The shale is too siliceous to be used in the manufacture of cement. The formation has a maximum thickness of 75 feet. It is well exposed along the river bluffs south of Hannibal and above and below the junction of the north and south forks of North river.
The following analysis, from Vol. XI of the reports of this Bureau,
illustrates the siliceous character of these beds.
Silica (SiO2) .................................... 75.70
Alumina (Al2O3) ............................... 9.60
Ferric oxide (Fe2O3) .............. ...... 1.79
Lime (CaO) ..........................     ......... 2.54
Magnesia (MgO) ................................ 2.11
Alkalies ....................... ............          2.65
Water (H2O) ...................................  6.16
Total......................................          100.36
The Louisiana (lithographic) limestone underlies the Hannibal sandstone and shale. This formation has a thickness of 55 feet, and is well exposed in the bluffs along Bear creek and the Mississippi river south of Hannibal. It is a fine grained, gray to buff colored limestone.
The beds are from 6 to 12 inches in thickness, and contain crystals and and small geodes of calcite. The chemical composition of this limestone varies at different horizons. Some of the beds are so high in magnesia as to render them unsuitable for use in the manufacture of cement.
The Hamilton shale underlies the Louisiana limestone. In places a thickness of 50 feet of this shale is exposed, although the beds outcrop over a relatively small area in the county. It has a bluish to brownish color, and is slightly arenaceous. The content of sand varies somewhat in different localities, but in general it constitutes an excellent material for use in the manufacture of cement. The principal out-crop occurs in T. 57, R. 6 and 7W., extending from one mile south of Warren along the south fork of North river for approximately four miles. A second important area extends from the county line along the creek west of Wesley approximately three miles. A smaller area occurs along Lick creek, in Secs. 6 and 7, T. 57, R. 6 W. Although not exposed, this formation occurs underneath the Louisiana limestone along Bear creek and along the Mississippi river south of Hannibal.
The shale could be obtained by tunneling, as practiced at the Atlas plant in the northern part of Ralls county. The following section, taken at "Lovers Leap," just south of the city, is typical for this portion of the county. 10 ft. LOESS stripping.
145 ft. Burlington LIMESTONE, upper portion very cherty and buff colored. Lower 40 feet heavily bedded with occasional nodules of chert. Lower 10 feet of this section probably Chouteau.
45 ft. "Vermicular" sandstone; buff to bluish in color, merges into sandy shale below. Shows tubular openings.
20 ft. Blue sandy SHALE (Hannibal.)
40 ft. Louisiana LIMESTONE in thin beds; fine grained, gray to buff colored. Contains calcite crystals and geodes.
The occurrence of the Hamilton group beneath the Louisiana is well illustrated by the following section measured along the south fork of North river about one and a half miles above its junction with the north fork.
10 ft. DRIFT.
65 ft. Sandy SHALE and SANDSTONE, filled with tubular cavities; typical Hannibal sandstone and shale.
30 ft. Fine grained, gray to buff colored LIMESTONE, containing crystals and small geodes of calcite. Regularly bedded Louisiana limestone.
35 ft. Bluish SHALE, slightly arenaceous; excellent quality for cement manufacture. Hamilton.
The Burlington limestone occurs at the crest of the bluffs along Bear creek, where it has been quarried extensively for the manufacture of lime. The purity of both the stone and the lime are shown in the analyses given under the description of the lime plants on the succeeding pages. The buff beds contain not only a higher percentage of iron, but they are also generally magnesian.
The following is a brief description of the lime plants operated by the Hannibal Lime Company, the Imperial White Lime Company and the Star Lime Company, in the vicinity of Hannibal. Under the name of the Hannibal Lime Company, the Marble Head Lime Company of Chicago operates two lime plants in this county,
one south of Hannibal and the other at Bear creek station, six miles west of Hannibal.
The Bear Creek is the oldest plant now operated in the county. Hagood and Loomis built this plant and sold it in 1868 to Munger Bros., who operated it continuously until 1902, when it was purchased by the Marble Head Lime Company. The plant consists of three kilns. Coal and wood are used as fuel.
The plant south of the city is the most easterly of those along the Bear creek bluffs. This was built by Munger Bros. and sold to the Marble Head Lime Company in 1902. It consists of three kilns. The plant of the Imperial White Lime Company was built in 1878 by the Waller Lime Company and operated by them until 1902, when
it was sold to the present owners. The plant consists of three kilns, each of which has a capacity of 125 to 140 barrels per day. The Star Lime Company operates two plants at Oak Wood station west of Hannibal. The original Star plant, consisting of two kilns was built by this company in 1893. In 1902 the plant of the Empire Lime Company, consisting of two kilns, was purchased by the Star Lime Company. This plant was erected in 1879, and has been in continual operation up to the present time. The company also owns a one kiln plant at Elmore, in Lincoln county. The daily capacity of the three plants operated by this company is approximately 700 bbls.
Wood is used as fuel. The lime produced at these plants is practically of the same grade, and is marketed under the names of Bear creek, Empire, Star and Imperial White Lime. All the quarries along the Bear creek bluffs south of Hannibal are
in the same ledge of limestone. The quarries are almost continuous  along the bluff as far west as Oak Wood station. The lower portion of the formation consisting of from 25 to 35 feet of heavily bedded, coarsely crystalline white limestone, is used exclusively at these plants. These beds are very free from chert, but contain 18 inches of buff stone near the middle of the face. Overlying this limestone there are from 10 to 50 feet of cherty, buff to gray limestone, which cannot be used for the manufacture of white lime. This cherty horizon increases in thickness as the beds are worked into the hill, and its removal is a source of great expense in quarrying. At the present time from 15 to 25 feet of waste is removed in order to obtain the desired limestone.
At the quarry of the Hannibal Lime Company the stripping has become so heavy that tunneling has been resorted to in order to reduce the cost of quarrying. At Bear creek the upper cherty horizon is not so thick, the stripping averaging not more than ten feet.
The stone is hauled to the kilns at the various plants in wagons
or carts. The introduction of tramways would facilitate the transfer of the stone to the kilns, since several of the plants have a comparatively long haul. The Star Lime Company has installed a crushing plant for the utilization of the overlying cherty limestone.
The following analyses of the limestone, taken from several reports made at different times, show the constant high calcium content of the limestone.