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Sidestrand - Trimingham
The section at Trimingham to Sidestrand is one of the wildest parts of the Norfolk coast. It is less easy to reach than most beaches and it's dramatic cliffs are subject to rapid erosion. The 50m high cliffs contain spectacular glacial sediments and structures and it's beach is a rich picking ground for petrologists and fossil hunters. But beware, it has many dangers.
The section cuts through the eastern end of the Cromer Ridge and shows the materials of which the ridge is composed and the nature of it's creation. The structural geology is dominated by pro-glacial thrusting that occurred at the margin of an advancing ice-sheet in the Anglian glaciation. Sheets of pre-existing materials such as chalk, Crag and Cromer Forest-bed sediments and earlier glacial sediments have been dislodged in thrust sheets that have been pushed forwards. Where the thrust has turned upwards it forms a ramp and one sheet has been thrust up over another.
The lowest of the Cromer Tills at Trimingham is a very compact and tough diamicton, which, due to its resistance to erosion, forms steep sections of cliff at beach level. When above the beach it makes a prominent step in the cliff profile. In it's upper parts, the till shows evidence that the icesheet was floating from time to time, and till was laid down under water. It shows horizontal banding, with drop stones and inter-leaving with sandier water-laid deposits that contain ripples.
The entire Sidestrand-Trimingham section is involved in a deformation event named by Jane Hart as the 'Trimingham disturbance'. This is characterised by large-scale open folding resulting from horizontal forces. Hart interprets this as pro-glacial thrusting, giving rise to low-angle pro-glacial thrusts and folds. Closely related, and more proximal to the ice is the set of conspicuous 'rafts' of Chalk and Lower Pleistocene sediments to the west at Sidestrand. We now see a distorted view of these structures, as coastal erosion is cutting obliquely to the direction of thrusting but the result is nevertheless very dramatic.
The till is dark brown in colour, sandy in texture with conspicuous, but relatively small, chalk and flint pebbles, cockle shells and erratics of Jurassic clay ironstones and crystalline igneous and metamorphics. Ice-scratched and faceted boulders are not uncommon, especially amongst the more far-travelled erratics. The larger and more resistant boulders end up on the foreshore and sink to the lower levels of the mobile beach material.
Park at the top of the slip road at Overstrand (TG 253405) or in the lay-by at Trimingham (TG 274388).
Reaching the beach from Overstrand: Go down the slip road east of the village (TG 253406), then clamber over slippery coast protection works.
Reaching the beach from Trimingham: Take the informal path down the cliff, which is reached via a footpath from the long lay-by on the B 1159 (TG 274388), across a field and through a small wood.
Note: Avoid in wet seasons, as the cliff is made treacherous by mud slides and cliff falls that can envelope a person up their thighs! Beware high tides will reach the cliff base and you can be cut off! A visit is best at, or just after, full moon or new moon when spring tides give low water in the middle of the day and maximum beach exposure.