The President thanked Dr Magraw for an interesting contribution to the complex problems provided by the Durham Permian and for release of the information on the N.C.B. offshore borings.
In the light of Dr Magraw's structural sections (which could be taken to imply an early phase of folding) he asked for confirmation that the sub-Permian floor was still plane, and he enquired whether the ridges of Yellow Sands showed internal sedimentary structure—in particular dune-bedding.
H. E. Wilson enquired for more details about the external structure of the basal sandstones. It seems inconceivable that an extensive dune area, of hundreds of square kilometres, could be submerged by an encroaching sea and still retain its dune form. Many of the photographs suggest a resemblance to the Dunnage Formation in Newfoundland and the Disturbed Beds of Denbighshire, and this might indicate a tectonic, rather than straightforward sedimentary, origin.
Denys B. Smith writes: I warmly welcome the release of so much new data from this region, which goes far towards confirming that the Permian sequence there is generally similar to that in central and east Yorkshire, where the full English Zechstein sequence is present. I also welcome Dr Magraw’s confirmation of the view presented in several recent publications that the basal Permian (Yellow) Sands are distributed in linear mounds on a flat or gently-sloping peneplane. However, his reinterpretations of the stratigraphy and sedimentary history of Permian marine strata in NE Durham are less acceptable, involving as they do a return to concepts prevailing