On the South-easterly Attenuation of the Lower Secondary Formations of England; and the probable Depth of the Coal-measures under Oxfordshire and Northamptonshire

Abstract

From the foregoing considerations the following conclusions may be drawn:— 1st. That during the deposition of the Tipper Palaeozoic and Lower Mesozoic Rocks an extensive tract of land existed to the north-west of the British Isles, which afforded the materials of which these rocks are composed; and it is probable that this region embraced the western isles and coast of Scotland. 2nd. That the Lower Permian Rocks were deposited in a channel, of which we can trace approximately the borders to the west and north-east; and that this group attains its maximum development along a band of country stretching west and east, from the southern borders of Salop, across Staffordshire to Warwickshire. 3rd. That at the close of the Permian Period there ensued considerable changes in the distribution of land and sea, involving a large increase in the latter. That a highway was opened between North Wales and Westmoreland, along which the sediment for the formation of the Lower Secondary rocks was transported by an oceanic current and spread over the plains of England, filling up old Palaeozoic valleys. 4th. That all the Lower Secondary formations decrease in thickness, and actually die out towards the south-east; that this attenuation is due to the increase of distance from the sources of supply, and the consequent failure of sedimentary materials which have come from land occupying the region of the North Atlantic. 5th. That there probably exists a tract of Coal-measures stretching from the southern borders of the Staffordshire and Warwick-shire Coal-fields