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2 September 2014
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Antrim Armagh Down Fermanagh Londonderry Tyrone
Portrush Causeway Coast Rathlin Glens of Antrim Slemish Mountain
Slemish Mountain ClipWatch Video Slemish Mountain map

Script

Key Points

Slemish, near Ballymena, draws us back into history for two reasons. It's a place of pilgrimage on St Patrick's Day, but it's also one of the clearest pieces of evidence of the area's volcanic past.

As we fly around the mountain, it becomes more obvious that what we're looking at is a huge plug in the earth where magma once oozed to the surface. It's been a while since any eruptions were seen here, though. The material that makes up this plug is estimated to be about 60 million years old.

The rock is known as dolerite. It's related to basalt, but has much larger crystals which are visible to the naked eye. That's a sign that the volcanic flow cooled relatively slowly.

Ireland's patron saint is thought to have walked these slopes for six years after being taken into slavery at the age of 16. He worked for a master named Milchu, herding swine and sheep. And according to his writings, it was here that St Patrick turned to prayer as his only consolation. He escaped, became a priest and began his mission to convert the Irish to Christianity.

The reason why Slemish dominates the skyline is that the land around it is relatively flat for as far as the eye can see. But even this flatter land is volcanic. Geologists reckon that lava flowed here for around two million years, creating the Antrim Plateau. It covers most of County Antrim and extends into other counties, too.

Slemish is the biggest of a number of volcanic plugs dotted around the plateau.

Slemish is a volcanic plug in the earth where magma once oozed to the surface.

The mountain is the biggest of a number of volcanic plugs dotted around the Antrim Plateau.

Ireland's patron saint is thought to have walked these slopes for six years and it is now a place of pilgrimage on St Patrick's Day.



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