. The Vermilion iron-bearing district of Minnesota : with an atlas . \Shaft 55 joofeer Fig. 9.—Horizontal section through fourth and sixth levels of the Chandler mine. Pioneer ore body. The Chandler-Pioneer ore body, as well as the orebodies to the east, occurs at the bottom and comes part way up the sides ofa narrow canoe-shaped synclinorium whose axis trends about 80° E. Therocks in this vicinity have been very closely folded, and, indeed, slightlyoverturned, so that at the west end of the Ely trough both walls dijD at avery high angle to the north. As the result of tinderground work, i
. The Vermilion iron-bearing district of Minnesota : with an atlas . \Shaft 55 joofeer Fig. 9.—Horizontal section through fourth and sixth levels of the Chandler mine. Pioneer ore body. The Chandler-Pioneer ore body, as well as the orebodies to the east, occurs at the bottom and comes part way up the sides ofa narrow canoe-shaped synclinorium whose axis trends about 80° E. Therocks in this vicinity have been very closely folded, and, indeed, slightlyoverturned, so that at the west end of the Ely trough both walls dijD at avery high angle to the north. As the result of tinderground work, it is 218 THE VERMILION IRON-BEARING DISTRICT. found that the south wall dips at an angle of about 70^ X. The north wallranges from a vertical position to a dip of 80° to the north. However, thisnortherly dip does not continue tliroughout the trough, but, on the contrary,it is found to be reversed at the east end of the tr()ugh, where the walls areoverturned in the opposite direction to the walls at the west end, and now. Scale 250 Fip. 10.—Vertical east-west section through the Chamller mine. dip at a high angle—about 80°—to the south. It is not known exacthat what point in the trough this change takes place. It probablv occursabout the center of the trough, near the east side of the Pioneer reverse of dip is possibly caused by the occurrence of a small subor-dinate cross anticline, which has produced a warping in tlie strata, with an SOUDAN FORMATION. 219 eastward pitch. These facts are shown by the accompanying fig. 8, a vertical section across the extreme western end of the basin, thereis shown a narrow synchne with both foot and hanging walls dipping to thenorth. In fig. 9 there may be seen horizontal sections through the fourthand sixth levels of the Chandler mine, with position of section shown infig. 11, indicated by line A-B. From study of this figure in comparisonwith figs. 8, 10, and 11 we see that farthest west and nearest th
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