Page. PLATE I. Generalized columnar section of the coal-bearing rocks 12 II. A, View of Potato Hill; B, Exposure of Hartshorne sandstone south 16 III. A, Exposure of the Hartshorne sandstone near Piney Creek, east of 18 VI Page. PLATE IV. A, Jointing of sandstone in quarry at Cabin Creek; B, Irregular V. Breaker at Scranton Anthracite Coal Company's mine, Spadra VI. Geologic and economic map and sections of the Arkansas coal 20 106 In pocket. FIG. 1. Map showing geographic position and railroad connection of the 2. Outline map of Arkansas coal field, showing mining centers, rail- 3. Graphic sections of upper part of Atoka formation 4. Graphic sections of Hartshorne formation.... 5. Graphic sections of Spadra shale......... 6. Graphic sections of Fort Smith formation..... 7. Graphic sections of Paris shale............... 8. Map showing structural features of Arkansas coal field.. 9. Diagram of Backbone Ridge fault 10. Diagram of Clarksville fault ... 11. Minor structural features of coal beds.. 12. Distribution of Hartshorne coal horizon .... 13. Diagram showing relation of topography to geologic structure at Long 14. Diagram showing relation of topography to geologic structure at 52 15. Profile of coal bed at Jenny Lind.. 53 16. Graphic sections of coal along outcrop from Bonanza to Oak Grove.. 54 55 18. Graphic sections of coal on outcrop from Hackett to Greenwood and 58 19. Graphic sections of coal on outcrop in Montreal, Burma, and Midland 60 20. Graphic sections of coal on outcrop from Huntington through Hart- 61 21. Characteristic sections of coal bed on outcrop south of Poteau Moun- 22. Map showing structure of Coal Hill-Denning district. 23. Graphic sections of coal at Denning. 24. Map of Spadra and Prairie View coal fields 25. Sections showing thickness of coal bed in Spadra district, and in un- 26. Graphic sections of coal in Prairie View field 27. Characteristic sections of coal bed at Charleston horizon.. 28. Diagram showing composition of coals from different parts of the 29. Diagram showing relative calorific values of coals from different parts 87 THE ARKANSAS COAL FIELD. By ARTHUR J. COLLIER. INTRODUCTION. Need of investigation.-Both the Carboniferous and the Tertiary rocks of Arkansas contain extensive deposits of coal, but only those of the older system in a field situated within the valley of Arkansas River and adjacent to the western boundary of the State have been exploited and are known to the trade. These coals have always borne a high reputation, but the demand for them has greatly increased in recent years. They grade from bituminous to semianthracite, and comparative experiments at the Geological Survey's fuel-testing plant have shown that coals of as good quality are not found elsewhere in the United States west of West Virginia." New uses for them have been found which indicate their importance in the commercial development of the Middle West. At the same time mining operations within the field have demonstrated that its structure is more complex and the known areas of workable coal more limited than the results of earlier surveys would indicate. For these reasons a number of operators and dealers in Arkansas coal called on the United States Geological Survey for more definite information regarding the extent and geologic structure of these coal beds, and in compliance with this demand a detailed reconnaissance investigation of the field was made from March 1 to August 1, 1906, the results of which are embodied in this report. Personnel.-In both the field and the office the writer was efficiently assisted by Mr. Carl D. Smith, who was already familiar with the problems involved, through his previous connection with the survey of adjacent coal fields in Indian Territory, and who was identified with this investigation throughout both the field and the office work; by Mr. Sidney Paige, who participated in the field work during the first two months of the season, before his departure for Alaska, and after his return assisted in preparing some of the maps; and by Mr. R. D. Mesler, who brought to this work an a Campbell, M. R., Classification of coals, in Report on the operations of the coal-testing plant, 1904: Prof. Paper U. S. Geol. Survey No. 48, 1906, pp. 156–173. |