What makes Pinhay Bay so geologically interesting is the range of fossils that can be found from the Jurassic Lias (fish, ammonites, shells and belemnites) and from the Cretaceous Chalk (echinoids, shells and sea urchin spines).
♦ Pinhay Bay can be reached by driving down to Monmouth Beach, which is just past Lyme Regis, and walking along Chippel Bay (also featured on this website).
♦ Once you pass the headland at Chippel Bay, the next bay is Pinhay Bay.
♦ This location is accessed by a long walk and, therefore, is only suitable for older children.
♦ Ref: 50.71294°N, 2.96478°W
FIND FREQUENCY: ♦♦♦ – The variety of geology at Pinhay Bay means you never know what you might find. Echinoids are the most common find, but ammonites from the Blue Lias can also be found and lovely examples of some huge ones can be seen on the wave cut platform. (Do not hammer these – leave them to be enjoyed by others.)
CHILDREN: ♦♦♦ – This location is accessed by a long walk and, therefore, is only suitable for older children.
ACCESS: ♦♦♦ – It is quite a walk to this site along the beach from Lyme Regis or Monmouth (just west of Lyme Regis). Please check tide times.
TYPE: – Most fossils are found in the fallen blocks, which can be seen on the foreshore or at the bottom of the cliffs in the scree. During scouring conditions, the Lias is exposed as ledges on the foreshore and these yield ammonites, many of which are quite large (do not try to extract these).
It is more difficult to find fossils in the Lias here than in Chippel Bay, as the beds are higher up. However, past cliff falls have yielded large ammonites and nautili. Many fossils can also be collected from the chalk at Pinhay, including echinoids, shells and crinoids. A range of fossils can also be found in the Upper Greensand chert beds from the top of the Lower Cretaceous (Albion), but these are very poorly preserved.
West of Seven Rock Point, younger rocks contain the ammonite Psiloceras. In the UK, these are regarded as marking the base of the Jurassic. At the head of Pinhay Bay, Triassic beds exposed on the foreshore can yield a range of bivalves.
Walking into Pinhay Bay from Lyme Regis, the junction of the Triassic (Penarth Group) with the overlying Jurassic strata of the Blue Lias Formation is found. The actual boundary sits within laminated limestones and shales, about 2.5 metres above the top of the clearly visible White Lias Formation, of the Langport Member, but the boundary is not conspicuous. This late Triassic limestone of the White Lias Formation lies below the Blue Lias and is eventually cut by a fault, so it is not visible to the west of the bay.
The Triassic rocks of the Penarth Group, are found on the foreshore and at the base of the cliffs. These Rhaetian aged rocks contain a range of compacted moulds of small aragonitic bivalves and gastropods, including Rhaotavicula contorta, Chlamys valonensis and Protocardia rhaetica, which can all be found.
The White Lias (Langport Member) is clearly seen in the cliff as pale green or grey limestones. White Lias is a rare, fine-grained form of limestone and getting the name ‘lias’ from the quarrymen’s dialect for ‘layers’, referring to its natural state when quarried. White Lias is part of the Penarth Group, a multi-layered bed of stone formed from shale and limestone. At its base is a bone-bed yielding ancient marine, reptilian and ammonites, although such occurrences at Pinhay Bay are seldom.
Walking west of Seven Rock Point, younger rocks can be seen above. These overlie the 19m of Blue Lias, and include Cretaceous Upper Greensand and the Chalk from the Lewes Nodular Chalk and the basal part of the overlying Seaford Chalk Formation from the Upper Turonian to the Coniacian. These beds are not accessible but fallen blocks on the beach can reveal a range of fossils.
Common sense when collecting at all locations should always be used and prior knowledge of tide times is essential. The two headlands at Pinhay bay and the headland between Pinhay and Chippel Bays are often reached by the sea at high tide. Therefore, you should ensure that you can return in adequate time to pass these points, especially since this location involves long walks. In addition, falling rocks and mudslides from the high cliffs are a risk. If using a hammer, stay away from the cliff face, as sound vibrations can cause rocks to fall from the cliff.
Due to the range of both soft and hard layers at Pinhay, it is best to take both a hammer and a pick, together with a chisel and safety goggles. A lump hammer may come in useful, as there are a number of large chalk boulders, which can be split. For fossils from the older harder chalk, small bags are fine for getting them home. However, fossils from the softer, younger chalk and Lias can be much more fragile, so these should be carefully wrapped and placed in containers or individual bags.
This site is an SSSI. This means you can visit the site, but hammering the bedrock is not permitted. For full information about the reasons for the status of the site and restrictions please download the PDF from Natural England – SSSI Information – Pinhay Bay