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-12- Geology The general geology of the North Park region has been well-established by numerous United States Geological Survey investigations, the most notable of which are Beekly (1915), Hail (1965, 1968) and Kinney (1970, 1971). The North Park region can be geomorphically classified as an intermontane basin, enclosed by the Medicine Bow Range to the east, the Park Range to the west, and the Rabbit Ears Range to the south. The resultant structural basin is truncated to the north by the Independence Mountain Fault. This basin contains sediments ranging in age from Triassic to Quarternary, In addition to the broad synclinal fold which formed the overall structural basin of the North Park region, considerable local folding and faulting has also occurred. These local folds and faults are probably the result of compression caused by the formation of the larger synclinal trough. The McCallum Anticline lies between the Michigan and Canadian Rivers, east of the town of Walden (Figure 3), Structurally, the anticline is doubly plunging and is asymmetric about its axis. To the north, where the anticline plunges northwest, the strike is approximately N45oW. To the south, the structure begins to change strike as the crest of the anticline plunges almost due south. Except near both noses, the anticline tends to be asymmetrical, with the more steeply dipping limb to the east side. At the Marr and Canadian Strip mines, the sediments on the eastern flank are near vertical or even overturned, In the area of the Bourg Mine, the strata on the east limb of the McCallum Anticline dip as much as 41o to the northeast. The Bourg Mine is flanked on the northeast by the Ballinger Anticline. The axis of the Ballinger Anticline joins the axis of the McCallum Anticline in Section 21, T9N, R78W. The Ballinger Anticline plunges to the northwest and strikes N35oW. The McCallum and Ballinger Anticlines form the limbs of the Bourg Syncline. This syncline is asymmetric, strikes N50oW and plunges 4 to 8 degrees to the northwest. The entire Bourg Strip life-of-mine plan area is within the Bourg Syncline. The Ballinger Anticline structurallly separates the Bourg Syncline from the Johnny Moore Syncline. The Johnny Moore Syncline is an asymmetric syncline, strikes N45oW, plunges to the southeast, and is flanked on the west by the McCallum Anticline. Both the Marr Strip and the Canadian Strip coal mines are located on the western limb of the Johnny Moore Syncline, The Canadian Strip is mining the nose of the McCallum Anticline, while the Marr Strip is mining the east limb of the McCallum Anticline. The intense folding of the rock strata has produced numerous faults in the general area. Faulting increases at the noses of synclines and anticlines. Stream channels have developed in several of the fault zones.