Beyond The Jurassic Coast: East of Old Harry Rocks
Although the Jurassic Coast, effectively ends just north of Swanage at the chalk pinnacles known as Old Harry Rocks, there are still several miles of Dorset coast to explore before encountering the Hampshire border just east of Christchurch. The coast runs north from Old Harry to South Haven Point - the end of the Minehead to Poole South West Coast Path - passing the beaches of Studland Bay en route. A ferry crosses the mouth of Poole Harbour and deposits its cargo at Sandbanks on the eastern end of Poole Harbour. East of the Sandbanks peninsula the beaches of Bournemouth take over and lead east to Christchurch where the border is marked by the River Avon, just east of Christchurch harbour.
Exploring the Coast
There is an excellent three mile walk (six miles if it is made into a circular walk) possible from Bournemouth Pier to Poole Head, just east of the Sandbanks peninsula. The walk offers a not too strenuous way of exploring this part of the Dorset coast with lots to interest the amateur geologist as well as the casual rambler.
The underlying clays and sandy rocks in the landscape date mainly from the Tertiary Period and were laid down about 40 million years ago. These are overlain by Quaternary 'head' and river gravels of the Pleistocene Period (less than 2 million years old). The intermediate strata was eroded prior to the Pleistocene so that there is now an unconformity. Its make up and structure can now only be guessed at.
Walk this way
Walking West from Bournemouth Pier, you climb towards Durley Chine. The rock under your feet is of the Branksome Sand formation (37 to 42 million years old). This is overlain by the slightly younger Boscombe Sand, laid down in shallow seas about 37 mya. This is topped of, to the west of the lift at West Cliff, by Pleistocene gravels and sands dating from just 1.8mya. Care should be exercised around here as landslips are prone to occur.
Continuing southwest as you near the valley or 'chine' of Durley Chine, the rocks under you are once again Branksome Sand. The younger Boscombe Sand does not feature here, nor does it on the whole journey west to Poole Head. West of Durley Chine, the cliffs consist solely of Branksome Sand and are again overlain by a thin layer of Pleistocene gravels. The route up the valley of Durley Chine is well signposted and is the first of seven such deep cut valleys, known as 'chines' in these parts, met on your way west. Just west of Durley Chine lies Middle Chine and further west Alum Chine.
Alum Chine and Branksome Dene Chine
Alum Chine is probably the best valley to explore from its southern end. From the sea, a number of paths lead off inland up the sides of the valley. One of the best vantage points from which to view the shape of the chine is from the bridge over the valley floor near Beaulieu Road. The next valley encountered is Branksome Dene Chine. The beach here consists of fine golden sand and is backed by beach huts next to the low cliffs. There is also a 13 acre Nature Reserve here.
Branksome Chine and Canford Cliffs Chine
Continuing west along the West Undercliff promenade, the next valley lies directly behind Branksome Beach and is unsurprisingly called Branksome Chine. Between Branksome Chine and Canford Cliffs Chine, the Branksome Sand formation is very clearly visible. Canford Cliffs Chine runs southwesttowards the Sandbanks peninsula. It is sandy and flat and the surrounding water is quite shallow. this makes Canford Cliffs popular for watersports, windsurfing and parasailing.
Southwest of Canford Cliffs Chine lies Flag Head Chine, just seaward of St Anne's Hospital. This is the last of the seven valleys on your way southwest towards Poole Head.