. Transactions . Here a ridge of limestone and lime-shales rises to a peak at itswest end, about 60 feet above the great terrace. At its east endlime-shale beds are exposed, above, beneath, and on each side of whichore has been mined. The long narrow ridge has been left standing like a wall betweenthe great ore-floor north of it and a deep wide trench of ore-groundsouth of it. The south side of the ridge shows alternate lime-shales and strati-fied ore, descending westward at about 10° beneath the massive whitelimestones marking the western peak, where there is a sharp contor-tion of the crysta
. Transactions . Here a ridge of limestone and lime-shales rises to a peak at itswest end, about 60 feet above the great terrace. At its east endlime-shale beds are exposed, above, beneath, and on each side of whichore has been mined. The long narrow ridge has been left standing like a wall betweenthe great ore-floor north of it and a deep wide trench of ore-groundsouth of it. The south side of the ridge shows alternate lime-shales and strati-fied ore, descending westward at about 10° beneath the massive whitelimestones marking the western peak, where there is a sharp contor-tion of the crystalline beds and, possibly, a reversal of the diptowards the south. Here is exhibited the feature of .crumpled beds between uncrum-pled beds, showing great lateral pressure, which would happen inalternate beds of resisting and yielding limestone and shale, thewhole mass settling down upon itself as it changed its bulk, duringthe process of change into ore. Fig. 4. »J ■ ^ : § • fs •3 J N^k K^ ) ^ *N / ^ /. THE CORNWALL IRON-ORE MINES, LEBANON COUNTY, PA. 889 The limestones exposed on the north side of Middle Hill, in twolittle peaks, are equally isolated. These two peaks contain differentlimestones, one above the other, with ore between the two, betweenthem and the trap, and, of course, above them to the south. The diphere is evidently towards the south. But these beds can not betraced vertically or longitudinally in the hill; they show nowherein the slopes to the east, and cannot be found west of their presentposition, changing in all directions into ore.* Fig. 3 shows the relation of these peaks to the stopes, to eachother, and to the tongues of trap already mentioned. Southwestof these peaks there is another isolated outcrop of hard whitelimestone exposed in a low cut at the end of the railroad rock is much broken and no certain dip can be assigned to it,though it is probably to the south. It is in the midst of the oremass and, from its position, evidently ab
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
