On the shoreward side of the village Ellenabeich, is what at first looks like an atoll, a large very roughly circular line of rock apparently enclosing an arm of the sea.

This can look like a harbour from a distance. Actually, it is all that remains of the slate quarry that led to Ellenabeich's growth. This was started by the Campbells of Breadalbane in 1745,
And by 1842 new steam powered pumps meant that quarrying could take place to a depth of 250ft (72 m) below sea level, in a vast pit separated from the sea by just a narrow wall of rock.

A storm in 1881 breached the wall around Ellenabeich's quarry, and it was inundated by the sea. Fortunately, no one was in it at the time. As the slate here was nearing exhaustion in any case, this spelled the end of slate quarrying in Elleneabeich and the several hundred jobs it provided, (wikipedia)

Notes 1 The Quarry .........................Pip 1, Quarry Wall
Note 2 First Breech..........................Pip 2, The Quarry.

Another image shot in 16.9 therefore a large view would be appreciated.