Awesome Geology at Finn MacCool’s Causeway


Giants Causeway Self Portrait

Millions of years ago, back when giants ruled the Earth, a massive Irishman named Finn MacCool was challenged to a fight by the Scottish giant Benandonner. Now, as everybody knows, giants can’t swim, so MacCool, an expert mason, built a stone walkway across the North Channel to the coast of Scotland so the two behemoths could meet.

Gunning for a fight, Benandonner stormed across the sea on the walkway and pounded on MacCool’s door. Peering through the keyhole at his oversized opponent, MacCool lost his nerve. His wife, Una, told him to put on her bonnet and get in bed, then she answered the door, telling Benandonner her husband was out and she was home alone with their baby. When Benandonner saw the size of MacCool’s “baby” he said, “If that’s the baby, how big is the giant?!” and ran all the way back to Scotland in fright, tearing up the walkway as he went.

The remains of Finn MacCool's walkway

The remains of Finn MacCool’s walkway

That’s one version of how the Giants Causeway came to be. Another version: around 60 million years ago, a spate of violent volcanism pushed molten basalt up through the soft chalk beds of Northern Ireland, erupting a massive lava plateau along what is now the Antrim Coast. In some places, the lava cooled so rapidly that it contracted along natural joints in the solidifying rock. Over time, erosion sculpted out three causeways, paved with more than 40,000 hexagonal basalt columns known as the Little, Middle and Grand Causeways. Many more columns can be seen overhead along the cliffs along the coast.

That’s maybe a more scientific explanation, but Scottish geology does corroborate the Finn MacCool legend: a similar causeway of hexagonal columns from the same lava flow is found all the way across the Irish Sea, on the Isle of Staffa!

The Little, Middle and Grand Causeways (left to right), photographed from above.

The Little, Middle and Grand Causeways (left to right), photographed from above.

I came to Northern Ireland for a week mainly to visit the Giants Causeway. I’ve sought out columnar basalt in a few other places, most notably at Cabezon Peak in New Mexico, the Devils Postpile in the Sierra Mountains of California and the Devils Tower in Wyoming.

As Ireland’s only World Heritage Site and a major tourist draw, the Causeway can get crowded, so I spent the night at the Whitepark Bay Hostel just up the road, arrived at the Causeway at dawn and had the place all to myself for over an hour. I’m always amazed by how few morning people there are in the world! As with many much-anticipated attractions, the Causeway wasn’t nearly as big as I expected – Cabezon, the Postpile and the Tower are all more formidable – but the setting along the coast was spectacular and I walked over the columns all the way down to where Ireland meets the sea.

Early morning at the Causeway

Early morning at the Causeway

Geometric Tide Pool Self Portrait

Geometric Tide Pool Self Portrait

Pentagonal Tide Pool

Pentagonal Tide Pool

Calm seas today. I would love to see this place in a storm!

Calm seas. I would love to see this place in a storm!

The Giants Causeway juts out from under Ireland’s towering northern coast (just east of Bushmills, home of the famous Irish Whiskey distillery), and the morning light on the dark, north-facing rocks wasn’t quite right for photographs. So after reveling in my quiet morning at the Causeway, I left to explore more of the coast, planning to come back in the evening for another round of photos.

After hiking a loop up the Shepard’s Steps to see the Causeway from above, I headed to another nearby attraction: the Carrick-a-Rede Rope Bridge. Every spring for nearly 200 years, fishermen have strung a rope bridge between the mainland and the small island of Carrick-a-Rede to gain access to the salmon-rich fishing grounds around the island. At five pounds, the bridge toll is a bit steep, but I was first in a very short line and got to cross the bridge back and forth a dozen or so times, so I feel like I got my money’s worth. Plus, while I was there, the sun came out in force for a few minutes. And here I thought it rained all the time in Ireland!

Caerrick-a-Rede Island

Carrick-a-Rede Island. The name means “rock in the road”. Love that bright blue water!

Crossing the bridge- max 8 people, no two-way traffic.

Crossing the bridge- max 8 people, no two-way traffic.

My turn!

My turn!

Don't Look Down! Too late...

Don’t Look Down! Too late…

View from the island

View from the island

Sunshine in Ireland!

Sunshine in Ireland!

By the time I returned to the Causeway it was literally crawling with people. I don’t know if everybody was conspiring to recreate that famous Led Zepplin album cover, or if tourists really are that unsteady on uneven rocks. I found an out of the way spot to sit and people watch, catching snippets of German and Japanese as people from all over the world swirled around the rocks. Then, miraculously, just before sunset, almost everybody boarded a shuttle bus and left, right before the sun splashed across the Causeway for 15 minutes and made my day:

The Glorious Giants Causeway

Evening light Self Portrait

Evening light Self Portrait


End of the day: just me and two red-shirted rangers

I’m not done with the Causeway Coast quite yet- I’m planning an 11-mile hike linking the Carrick-a-Rede Rope Bridge and the Giants Causeway on the Coast Trail! Stay tuned!

About theblondecoyote

Mary Caperton Morton is a freelance science and travel writer with degrees in biology and geology and a master’s in science writing. A regular contributor to EARTH magazine, where her favorite beat is the Travels in Geology column, she has also written for the anthologies Best Women's Travel Writing 2010 and Best Travel Writing 2011. Mary is currently based in western Colorado. When she’s not at the computer she can usually be found outside -- hiking, skiing, climbing mountains and taking photographs. Visit her website at
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17 Responses to Awesome Geology at Finn MacCool’s Causeway

  1. Pingback: Driving (on the left!) Up the Antrim Coast | Travels with the Blonde Coyote

  2. Franz Fuls says:

    Such a great story! The giants’ story sounds very credible, and the scientific explanation looks like complete hogwash!!

    I’m posting a link to

  3. Erica says:

    I love the two tales 😉 And I’m also surprised at the lack of morning people. I’m very guilty of being one of the sleeper-inners, but on more recent trips, I’ve been finding myself waking up early, even just to catch the sunrise before catching one last wink before I wake up for real.

    I actually saw a really similar rock formation on Jeju Island in South Korea. They’re called the Jusangjeolli Rocks there.

  4. Joanna says:

    Amazing story! That bridge seems terrifying..

  5. Tiffani says:


  6. bonsai eejit says:

    Glad you liked what you saw of my our North coast 🙂 I’ve been following your blog for a while and mentioned the causeway to you a while back. Being from ‘Norn Iron’ 🙂 I know it well. If I knew you were here I would have directed you east along the coast towards Ballycastle to a little place often forgotten about and usually free from tourists, Kinbane Castle. Have a look here: Hope you left us with a good opinion of our wee country, often remembered for the wrong reasons.

  7. Ive always wanted to go there, some day.

  8. patti leonhardt says:

    Fabulous place, like to put it on the bucket list. my grandmothers maiden name Karrick, do you suppose it means rock also?

  9. Beautiful pictures, and a beautiful country. You got lucky with the sun, as I have in Washington and Oregon; I am told I have seen more of Mt Rainer and Hood than some natives:) Thanks for sharing.

  10. Pingback: Best Hikes on Earth: The Causeway Coast Trail | Travels with the Blonde Coyote

  11. Hi Mary – What a cool place and amazing rock formations. Love these photos and if I ever get to Ireland, I would love to the the Giant’s Causeway, however it got there. Best to you, Carol

  12. alongourway says:

    Great post! We were there the end of November a couple years back, and there were enormous full rainbows above the sea.

  13. Pingback: High Points On My Horizon: Santa Fe Baldy | Travels with the Blonde Coyote

  14. Great pics, you’ll need to add Micronesia to your list of places to see, the ruins on Pohnpei – Nan madol are built from columnar basalt. The mystery is how they moved the columns from the other side of the island where they came from a mountain similar to devils tower, this one is called chicken shit mountain though.

  15. Pingback: EARTH Magazine: A New “Travels in Geology” Collection! | Travels with the Blonde Coyote

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