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coal beds. Approximately 600 feet of conglomerate, tuff, vol- canic ash, sandstone, and shale comprise the North Park Forma- tion, which unconformably overlies the Coalmont Formation. The coal presently mined at the Canadian Strip Mine is the Sudduth Seam, which lies within the Coalmont Formation, approxi- mately 50 feet above the Coalmont-Pierre Shale contact. The thickness of the coal varies from fewer than ten to thirty feet. The Capron Coal Seam, situated stratigraphically approximately 2,400 feet above the Sudduth Seam, has been removed from the permit area by p 5laciation and erosion. The upper Sandy Member of the Pierre Shale, however, is still exposed along the Crest of the anticline, and serves as the major aquifer in the permit area (pp. 4 and 4, Appendix C, Volume 1 of the permit application). The geology of the mine plan area has been divided into six hydrologic zones: 1) alluvial deposits of the North Fork of Bolton Draw; 2) terrace gravel deposits laid down by the Canadian and Michigan River system on the upland divide areas; 3) the interbedded sandstones and siltstones of the Coalmont Formation directly above the coal; 4) the Coalmont coal; 5) the shale zone lying between the coal and Pierre Formation; and 6) the Upper Sandy Member of the Pierre Formation. The alluvial deposits are discussed at length within the Alluvial Valley Floor (AVF) section of this TEA. The terrace gravel deposits collect water that infiltrates the surface as rain or snowmelt, and then migrates downward until it reaches the erosional boundary with the consolidated sediments of the Coalmont. Most of this ground water then follows the gradient of this interface and is released downgradient as springs or seeps. The applicant has indicated (page 6, Appendix C; Figure 2A of Addendum II) that one such seep occurs in the extreme headwaters of the North Fork of Bolton Draw. -23-