Harrow and Hillingdon Geological Society
Report on the HHGS field trip to Hastings: the Ashdown formation and Wadhurst Clay of the Hastings Beds at Pett. 11 July 2004
Another interesting field trip had been arranged. This time to the complex Lower Cretaceous of Sussex just east of Hastings. The weather was somewhat threatening, but we managed to get through the day without too much trouble. We were fortunate in having three leaders knowledgeable about this section of our fascinating southern coastline and, as usual, we were provided with 3 detailed handouts packed with diagrams showing the sections to be studied as well as drawings of the fossils which we might be lucky enough to find during the day. The field trip was led by Peter & Joyce Austen and Richard Baldwin, and the 18 attendees, including children, were able to benefit from their expert knowledge during the day.
We set off down the beach on a falling tide and went from Cliff End in the Wadhurst Clay to well beyond Fairlight Cove. The depositional environment was once believed to be deltaic, but it now seems to have been a low lying plain crossed by meandering rivers with Iguanodon herds chomping through the vegetation. Indeed pieces of lignite were among the items found by members, as well as fallen fragments of the Cliff End Bone Bed.
Structural geology was provided by a lesson in faulting, with the Cliff End normal faults near the start of our walk and further on the Haddock and Fairlight reverse faults. The effect of these faults is to provide access to a large range of strata along a relatively short walk despite the gently dipping nature of the section.
The sedimentary geology in this location is complex, and we were lucky to have experts to point out to us some striking features. By walking out near to the low water shoreline and stepping gingerly over the seaweed encrusted rocks, we could get a superb view of trough cross bedding in the sandstones of the Ashdown Beds.
Palaeontology enthusiasts were shown some newly identified quillworts and once we had had these pointed out to us, a number were identified by the party. Iguanodon footprints were clearly identified and Bob Maurer provided an on-site demonstration of the characteristic print followed by a sideways splurge. We were duly convinced by the identification of evidence of bioturbation, that is trampling by groups of Iguanodon in what was then soft sediment. In many ways trace fossils are the most stimulating finds for the imagination as they allow us to conjure up live animals rather than corpses.
At Fairlight Cove we found an intrusive alien wall of Larvikite which has been installed to provide protection for some houses perched dangerously near the cliff edges. Perhaps it is a vain effort, for much cliff erosion is created by rain and runoff, and not by wave action. It certainly has scarred a very impressive stretch of coastline.
As we returned to our starting point, we could see clear traces of the Pett Level submerged forest. This has been dated to 5200BC and is ascribed to rising sea levels by the official notice board. However seas do indeed rise but lands can sink, and a recent program on submerged forests in the Solent area has suggested that Southern Britain has subsided in recent times, pivoting in response to the delayed isostatic rise of Scotland following the retreat of the ice cap.
Despite the weather, which became more threatening, we had another interesting day along a stretch of our magnificent coastline.