Coastal relics from the last Ice Age

Clach Tholl, coastal arch at Port Appin

Just south of Port Appin in Argyll is a coastal arch called Clach Tholl (in Gaelic, meaning ‘the rock with a hole in it’).  But far from being washed by the waves, it stands a good 50 yards or so from the shore, well above the high tide mark.

So how did it get there?

At the end of the last Ice Age, about 11,000 years ago, the land was finally free of the heavy burden of ice.

Just like a piece of rubber rebounding after being squashed, the land slowly began to rise.  The ice sheets were melting and sea levels were also rising, but the uplift in the land was far greater.  As a result, some of Scotland’s beaches and coastal cliffs, including the arch of Clach Tholl, were left high and dry.

A few miles to the south, the Dog Stone (Clach a’Choin), is another example of the same process.   The Dog Stone is an isolated sea stack just below Dunollie Castle near Oban.  According to Celtic mythology, it is so named because this is where the warrior Fionn MacCumhail, leader of the legendary Fianna, would chain his dog, Bran.  (This is the same Fionn MacCumhail who ate the salmon which had feasted on the hazelnuts of wisdom… you can read more Under the Hazel Tree!)


Photos copyright © Jo Woolf


  1. I never knew about these features! Nature is amazing. I have some historical fiction books that mention the Fianna – now those books are like the tales of old (Sevenwaters trilogy by Juliet Marillier).

    • I’m glad you think it’s amazing too, Rachel! The more you look, the more evidence there is, and it’s all right there, all along that coastline. Those books sound good, I might look them up!

      • They are fantastic – they are written/targeted at young adults, but I have found I have read into them a lot more now I am older, there are plenty of hidden meanings and things I never twigged about when I was younger.

  2. Sure wish I’d known there was a Dog Stone when I was in Oban–I would have paid it a visit! Hank would have saluted it in his own special way, too.

  3. Missed both of those, will have to have a look next time 🙂 Lovely photo of the loch.

    • Thank you! That was a lovely day, very soft muted lighting, then a spectacular sunset. It’s worth looking for the Dog Stone, right underneath Dunollie Castle. For the arch you’ll need to park at Port Appin and then walk around the peninsula.

      • Thank you, I have visited the castle and explored the museum there, but somehow have missed the dog stone or just never noticed it 🙂

  4. That archway looks a bit familiar, have I seen it once before in a different post? It’s quite an amazing structure. The last photo makes me think of midges for some reason.

    • Yes! Well remembered! We had a walk around there with Leonie & Andrew a year or so ago and I wrote about it on my Journal. I was looking at the pic of the arch again and thinking “There must be a reason for this!” Haha, yes I guess the last photo was taken on a still summer evening so the midges might have been present, but I don’t seem to remember being bitten! 🙂

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