The lake coal dominates the market as far south as Milwaukee, and it is only of recent years that Illinois coal has begun to go in any quantity as far northwest as St. Paul and Minneapolis. In the territory between these points there is much debatable ground, and if methods of storage can be devised so that the coal may be shipped in the summer, large increases in trade may be expected. The same is true of western Iowa and eastern Nebraska, where at present there is only a moderate trade. If, in addition to finding a solution of the storageproblem, water-transportation be made available, Illinois coal may become a dominant factor in the Northwest. It must be admitted, however, that this is far from being accomplished, and for the present, in extending the markets, reliance must be placed mainly on a campaign of education in the proper burning of high-volatile coals. The purchase of coal on specifications is also to be commended. This not only leads to closer studies of coal-bills and, conditions of burning, but, by means of the inspection-system, improves the mining and cleaning of the coal. While doubtless criticism can be fairly made of particular specifications, it is believed that the system itself will, in the long run, commend itself both to buyers and sellers. The Clinton Iron-Ore Deposits in Alabama.* A. Topography and Its Relation to Industrial Development, B. Distribution and Structure of Formations, C. Divisions of the Birmingham District, Division A (Description of the Ore-Beds), Division B, Division C, Division D, Division E, Division F, Division G, D. Mining Development, 2. Northeast Alabama, . IV. POSSIBLE ORIGIN OF THE ORE, V. RELATION OF ORIGIN TO QUALITY AND EXTENT OF ORE, PAGE. 75 76 76 77 82 85 85 88 88 88 88 89 95 95 105 106 107 108 111 112 113 114 119 122 125 125 126 132 2. Data and Results, VII. PRODUCTION AND CONSUMPTION OF IRON-ORE, I. INTRODUCTION. BRIEF and interrupted studies of the Alabama Clinton ironores have been made within the last four years by members of the U. S. Geological Survey. Reports on the progress of this * Published by permission of the Director of the U. S. Geological Survey. work have been published from time to time by the Survey.' A detailed report on the Birmingham district, with maps, has been completed, and will be published within the next year.2 In the following paper it is aimed to present only an outline of the geologic relations of the ores, since the Appalachian geology of Alabama has been discussed by many previous writers, but to describe rather fully the ore of the Birmingham district, and to discuss its relations and probable extent. II. OUTLINE OF THE GEOLOGY. 1. Stratigraphy. The pre-Pennsylvanian rocks exposed in and along the borders of the valley-regions of Alabama, range from middle Cambrian to Mississippian (Lower Carboniferous), and at the SW. extremities of the valleys these rocks are overlain by coastal-plain deposits of Cretaceous and Tertiary age. eralized section of the pre-Pennsylvanian Palæozoic rocks for the valley-regions is given in Table I. A gen TABLE I.-Section of Pre-Pennsylvanian Palæozoic Rocks in 1 Burchard, E. F. Iron Ores in the Brookwood Quadrangle, Ala., Bulletin of the U. S. Geological Survey No. 260, pp. 321 to 334 (1905). Eckel, E. C. The Clinton or Red Ores of Northern Alabama, Bulletin of the U. S. Geological Survey No. 285, pp. 172 to 179 (1906). Burchard, E. F. Bulletin of the U. S. Burchard, E. F. The Clinton or Red Ores of the Birmingham District, Ala., An Estimate of the Tonnage of Available Clinton Iron Ore in the Birmingham District, Ala., Bulletin of the U. S. Geological Survey No. 340, pp. 308 to 317 (1908). 2 Eckel, Edwin C., Burchard, E. F., and Butts, Charles. The Iron-Ores, Fuels, and Fluxes of the Birmingham District, Ala., Bulletin of the U. S. Geological Survey No. (in preparation). A. Clinton Formation.-The Clinton formation, in which the red ores occur, will be described somewhat fully here, owing to its particular interest in this connection. It consists in Alabama principally of sandstone, shale, and beds of impure hematite. The hematite-bearing beds, where unweathered, are calcareous and siliceous, ranging from a calcareous, richly ferruginous sandstone to a ferruginous, siliceous limestone. Beds of impure limestone are present in NE. Alabama, and in Georgia and Tennessee, but there appear to be no true limestone strata in the formation in the Birmingham district. The distinguishing feature of the formation is the relatively large quantity of iron oxide disseminated throughout all the sediments, either in the ferric or the ferrous state. While there are sharp lines of demarcation between certain beds of iron-ore, shale, and sandstone, many of these beds change from one to the other by gentle gradations. Consequently, there are in the section beds of ferruginous shaly sandstone and sandy shale, or the material may carry sufficient iron oxide to be styled a sandy ore or a shaly ore. As is well known, the ferruginous character of the Clinton formation is not peculiar to the southern Appalachians only, since rocks of equivalent age contain beds of hematite throughout the whole length of the Appalachians, as well as in such widely-separated localities as New Brunswick, New York, and Wisconsin. In Alabama the formation is thickest toward the NE., measuring there more than 700 ft., and at this end of the area the proportion of shale is greatest. With thinning of the formation towards the S. and SW., where it becomes generally less than 300 ft. thick, and locally thins to less than 200 ft., the proportion of sandstone increases. It is difficult, however, to apply one set of rules to all the areas of the Clinton strata in Alabama, particularly to strips of the formations that lie on opposite sides of a valley and are separated by structures that are, in the main, anticlinal. At Birmingham, for instance, Red mountain and West Red mountain lie nearly parallel to each other, generally only 6 or 7 miles apart, yet there are greater differences in the character of the Clinton formation at corresponding points in these ridges than there are between points on the same ridge separated by two to three times that distance. Sections on West Red mountain cannot be correlated Cp, Fort Payne Chert. Sc, Clinton Formation. h, Hickory Nut Seam. i, Ida FIG. 1.-STRIKE-SECTION, with those made 6 or 7 miles across the valley on Red mountain, but there is little difficulty in correlating sections made 12 to 15 miles apart on Red mountain. These conditions may perhaps be due to more abrupt changes in sedimentation from place to place in a direction at right angles to the shore-line of the body of water in which the sediments were deposited than parallel to this shore-line. There are, however, definite variations in composition from NE. to SW., as shown by a series of seven detailed sections on Red mountain, beginning NE. of Birmingham and continuing at irregular intervals along the strike of the beds for about 35 miles to the SW., as is illustrated in Fig. 1, a strike-section compiled from these detailed sections. These sections showed that the thickness of the Clinton formation on Red mountain near Birmingham varied from less than 200 to 358 ft., that there were at least four distinct ore-horizons at certain places, with possibly a fifth horizon, represented by a very ferruginous sandstone locally developed, and that not all these ore-seams are persistent throughout the series of sections. By way of contrast, six sections are given below, the first twobeing from NE. Alabama. Nos. 3 and 4 are typical of Red mountain in the Birmingham district, and Nos. 5 and 6 are characteristic of West Red mountain in the same district. 1. Partial Section of Clinton Formation near Battelle, Ala. 3 Burchard, E. F. The Clinton or Red Ores of the Birmingham District, Ala., Bulletin of the U. S. Geological Survey No. 315, pp. 136 to 139 (1907). Eckel, E. C. The Clinton or Red Ores of Northern Alabama, Bulletin of the U. S. Geological Survey No. 285, p. 174 (1906). LONE PINE GAP |