Sand, Shingle and Shipwrecks
PUBLISHED: 10:29 30 November 2007 | UPDATED: 14:57 20 February 2013
In this December/January issue, Derek Stonley unearths some of Cornwall's geological curiosities at Loe Bar, also the grave of HMS Anson, a 44-gun vessel that was shipwrecked 200 years ago this December. These geological curiosities are exposed by...
Cornwall is particularly blessed with what I like to call geological curiosities. They are exposed by the forces of erosion that have been acting upon unique configurations of rock formations. The end products of these forces are the splendid landscape features we see today, each with its own particular history to be unravelled. While the scientific explanation for these features is interesting in its own right, these curiosities are not merely passive in the landscape. They have, over the centuries, exerted a magnetic attraction upon mankind. Fascinating human stories have become inextricably linked to, and determined by, the underlying geology.
Loe Bar is the great strip of sand and shingle that runs for some two-and-a-half miles from Porthleven to Gunwalloe. The beach faces due south-west, and bears the brunt of the fierce Atlantic swells. It shelves steeply into deep water, and signs are all about warning that it is dangerous to bathe at any time. Even on calm days, waves can heave up as if from nowhere, rushing up the sands and sucking back the unwary in the strong undertow. In times of storm, the foreshore is a terrifying maelstrom of wild water.
Loe Bar itself is what is termed a barrier beach. It obstructs the flow of the River Cober to form Loe Pool, the largest freshwater lake in Cornwall. The Bar is now a Site of Special Scientific Interest, a specialised habitat for a number of rare species. The impressive yellow horned poppy, sea holly, sea pea and sea campion all maintain a precarious foothold in the barren, unstable sands. At night, the Cornish sandhill rustic moth, which is found nowhere else in the world, flitters about this strange place.
There are other barrier beaches along the south coast of England. Slapton Sands and Chesil Beach spring to mind, but Loe Bar's formation is enigmatic. Much of its sand and shingle consists of flint, for which there is no known source in Cornwall. Flint originates in the chalk formations in the eastern half of England, and the nearest present-day outcrops of chalk are at Beer in East Devon, a good 100 miles from Loe Bar. It is thought that some 70 million years ago, the seas wherein the chalk was deposited, together with the siliceous skeletons of micro-organisms that produced the flint, covered the lower parts of what is now Cornwall. The soft chalk was subsequently eroded away, leaving a scattering of flint behind as a resistant residue.
We know from history that the town of Helston, which received its charter from King John in 1201, was formerly a small port on the tidal River Cober. During the 13th century, Loe Bar grew to such an extent that the port was cut off from the open sea, forcing the burgesses of Helston to negotiate for rights in the port of Gweek on the Helford River. It is probable that Loe Bar's dramatic growth at that time was a consequence of the final inundation of the forests that once flourished in Mount's Bay. Destruction of the trees would have loosened the soil, releasing an enormous supply of entrapped flints, which were then free to be piled up along this section of the coast by the south-westerly gales.
Loe Bar has been the scene of many shipwrecks. December 2007 marks the bicentenary of one of the most famous sea disasters, the wreck of the frigate HMS Anson, on 29 December 1807. The Anson was a 44-gun vessel that had left Falmouth on Christmas Eve to join a fleet blockading the French port of Brest during the war with Napoleon. She ran into a severe gale, and although she reached the French coast, the captain decided to run with the wind and seek the shelter of Falmouth once again. On the afternoon of 28 December, the ship became embayed in Mount's Bay, could not claw her way to safety against the gale, and was forced to drop anchor off Loe Bar. The anchors held until the following morning, but then the chains parted. An attempt was made to run the vessel aground, but she broached to, and the mainmast crashed down. This fortuitously provided a means of escape for some, but 120 sailors, including the captain, were swept away by the raging waves.
Watching the terrible scene unfold, with people being drowned almost within touching distance of safety, was Henry Trengrouse, the son of a Helston cabinetmaker. He was so affected by the disaster that he began to experiment on a simple means of carrying a lifeline to a wreck. After ten years of struggle and expenditure of his own money, he perfected a portable rocket apparatus which was put into production by the Admiralty. Trengrouse's meagre reward from the Admiralty was £50, and another 35 guineas was forthcoming from the Society of Arts. The rocket apparatus has subsequently been the means of saving thousands of lives, with the catalyst for its invention being that dreadful day 200 years ago at Loe Bar.
In times of storm, Loe Bar's foreshore is a terrifying maelstrom of wild water
HOW TO GET THERE
The simplest approach is to walk a mile along the coast from Porthleven to the north end of the Bar. Alternatively, take the A3083 south from Helston. After one mile, turn right immediately before the bridge over the road marked 'HMS Seahawk'. Follow this unsigned lane for 1.4 miles to
a junction marked Loe Bar Sands. Continue for 0.5 mile to Chyvarloe National Trust car park. Walk a further 0.5 mile to the south end of the Bar.
WHAT TO LOOK FOR
• Beside Bar Lodge, above the north end of Loe Bar, is an excellent National Trust explanatory plaque.
• A cross commemorating the HMS Anson disaster is situated close to the coast path.
• Find, but do not pick, rare sea holly, yellow horned poppies, sea campion and sea pea on the Bar sands.