THE GATE RIDGE ANTICLINAL succeeds the first, or Southern, basin. The strata here present the same appearance on their north dip as in the Sharp Mountain. A singular phenomenon is here presented of south-dipping angles on both sides of an anticlinal and also on both sides of a synclinal axis. All the strata appear to dip under the Sharp Mountain, and the veins outcropping in the Gate ridge axis all dip south, apparently as distinct and independent beds, though half of them are really north-dipping veins of the second basin, and only half south-dipping veins of the first basin. It will be noticed in figure 74 that the Gate vein M is also the Salem vein M,—the Gate being the north dip of the second basin, and the Salem the south dip of the first basin.
This singular formation was for a long time a mystery to our most practical miners ; and even now it is rare to find any but professional men who fully comprehend this feature of the anthracite regions ; for not only in this portion of the field, but in all the basins within it, many of the north-dipping veins have the appearance of south dips on their outcrops. The same feature is manifest in the Mahanoy portion of the Middle coal field, and it occurs sometimes, though rarely, in both the Shamokin and the Wyoming regions. We seldom find inverted strata in the south dips.
The Daddow Tunnel, which was driven south into the Sharp Mountain, a short distance above Port Carbon, about the year 1834, was the first effort to develop the veins in that side of the basin. We believe 14 beds, small and large, were cut; and though they all still dipped to the south, it was then first suggested that they eventually might change to north-dipping veins. The author preserved for a long period a section of this tunnel ;
but unfortunately it is now missing.
Geologists may think it strange that any difficulty should exist in explaining those irregular formations ; but the geologists of that day were even more at fault than the miners, and up to a late date the errors then published still misled the scientific world ; while palpable errors of a later date attest the fact that scientific men are not more exempt from this fallacy than the experimentally practical.
We think it may be justly stated that one of our old English miners was the first to suggest a theory to account for the repetition of the veins.
The first sketch ever made of the undulations of the anthracite measures was drawn by Mr. John Beadle, then managing the old Gate vein colliery for Messrs. Mann & Williams, on the walls of the mine-office ; and this sketch remained on the walls of that office for years, and was often dis cussed and observed by many who since claim for themselves the credit of originators. We know this to be correct ; and though the rough chalk sketch alluded to did not attempt a correct delineation, it still presented the suggestion, which has since been developed in fact, and which we now present in figure 74 as the result of thirty years' inquiry and proof.