On the Permian Rocks of the North-West of England, and their Extension into Scotland

Abstract

The Permian rocks of the county of Durham have hitherto been regarded as the type of this formation in England. In this county, however, excepting the middle member, the strata appertaining to this portion of the Palæozoic period are very imperfectly represented. Of this group the base is almost absent, the Penrith sandstones occurring only to a very slight extent as soft sandstones, supporting the base of the magnesian limestones—the equivalents of the Hilton series—and in many localities these sandstones disappear altogether. In the county of Durham the portions of the Permian strata which occur are transgressive on the coal-measures, and are spread out upon the eroded surfaces of the latter rocks. At Tynemouth, beneath the “brecciated limestone” forming the upper portion of the cliffs, this eroded surface is seen in the light-coloured sandstone supporting the Permian breccia-beds. This light-coloured sandstone is said to pass downwards into another sandstone with a purple tint, and the latter rests conformably upon shale which equally conforms to the seam of coal seen at Cullercoats and known as the Hebburn scam.