The High Wolds Escarpment: what lies beneath the Chalk?

Author: Derek Gobbett.

We met at the top of Painsthorpe Dale, a little to the north of Garrowby Hill. and descended along the track noting a discontinuous section in the lower part of the Chalk passing down through white chalk with small flints (Welton Formation) into grey and pink chalks (Ferriby Formation). The Black Band was not exposed. A little lower down were small exposures of red chalk (Hunstanton Formation). The floor of the valley was distinctly marshy and is underlain by the Upper Lias. However above the marshy ground a good exposure of the Lower Cretaceous Carstone was seen. 

The main outcrop of the Carstone lies to the south of the Market Weighton Block. To the  north the Lower Cretaceous is represented by the Speeton Clay. This area of Carstone would appear to be a small outlier in the middle of the MW Block.

The rest of the day was spent up and down the escarpment above Bishop Wilton. The Ferriby Formation, including the Black Band, was well exposed in the disused pit in Worsendale. The section here forms part of the series of landslips which characterise the chalk escarpment. After lunch in Bishop Wilton we climbed over landslips up the steep escarpment. The Chalk was poorly exposed near the top and below in the slipped area we found fragments of shelly limestone probably from the Lower Lias. Thus here, near the centre of the Market Weighton Block, most of the Jurassic is missing.