Qualla: Mount's Bay

Mount's Bay: Introduction

Sat, 23 May 2026 00:00:00 GMT

Photo credit Tom Corser, CC BY-SA 2.0 uk. At low tide on the beaches at Ponsandane and Wherrytown, on either side of Penzance, you can sometimes see them - the partially fossilised trunks of trees that grew here when the sea was somewhere else. Radiocarbon-dated to between six thousand and four thousand years ago, this drowned forest extended two to five kilometres further south than the modern coastline of Mount's Bay. Divers and trawlers still bring up its timbers from the seabed offshore. The bay you see today, with St Michael's Mount rising out of the water like a fairy tale, is geological youngster - a Holocene bay that flooded a Mesolithic landscape. Stand on Penzance promenade and look out across the half-moon of water, and you are looking across a sunken country.

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Image: Tom Corser | CC BY-SA 2.0 uk

Mount's Bay: The Shape of the Bay

Sat, 23 May 2026 00:00:00 GMT

Photo credit Nilfanion, CC BY-SA 3.0. Mount's Bay is the largest bay in Cornwall, arcing from Lizard Point in the east to Gwennap Head in the west. Its half-moon shape resembles Donegal Bay in Ireland and Cardigan Bay in Wales, though Mount's Bay sits in the rare position of being partly sheltered from the prevailing...

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Image: Nilfanion | CC BY-SA 3.0

Mount's Bay: The Drowned Forest

Sat, 23 May 2026 00:00:00 GMT

Photo credit Bob Embleton, CC BY-SA 2.0. About 12,000 years ago, as the ice sheets melted, sea level began to rise. Offshore surveys of Mount's Bay have found submerged erosional plains and valleys filled with deposits of peat, sand, and gravel - the cyclical record of a coastline that turned from wetland to coastal for...

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Image: Bob Embleton | CC BY-SA 2.0

Mount's Bay: Spaniards and Barbary Pirates

Sat, 23 May 2026 00:00:00 GMT

Photo credit Pauline Eccles, CC BY-SA 2.0. The bay's history is salted with violence from the sea. In August 1595, a Spanish naval squadron under Carlos de Amesquita, patrolling out of Brittany during the Anglo-Spanish War, came ashore in Mount's Bay and burned Newlyn, Mousehole, Penzance, and Paul over two days. A militi...

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Image: Pauline Eccles | CC BY-SA 2.0

Mount's Bay: Mines Beneath the Waves

Sat, 23 May 2026 00:00:00 GMT

Photo credit Rarb, CC BY 3.0. Tin made Cornwall, and Cornwall worked the tin even where it had to drive shafts below the high-water mark. An elvan dyke rich in tin runs almost parallel to Penzance promenade, about 240 yards offshore. From 1778 Thomas Curtis sank a shaft on the Wherrytown reef and built a twen...

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Image: Rarb | CC BY 3.0

Mount's Bay: 1755 and the Lisbon Tsunami

Sat, 23 May 2026 00:00:00 GMT

Photo credit Reiner Tegtmeyer, CC BY-SA 2.0. On 1 November 1755 the great Lisbon earthquake destroyed much of the Portuguese capital. About four hours later, around two in the afternoon, the resulting tsunami crossed open ocean and hit the coast of Cornwall. At Mount's Bay the sea rose ten feet at great speed and ebbed at t...

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Image: Reiner Tegtmeyer | CC BY-SA 2.0