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| An exposed coral reef at Ardmore Bay |
On
Day 5 of my tour of southern Ireland, I had no County Geological Sites to
survey and my only objective was to reach Co. Kilkenny and, being on a working
holiday, I just let the day unfold at a leisurely pace.
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| St. Declan's cathedral in Ardmore |
Working
my way around the estuary of the River Blackwater, after leaving Youghal, I decided to go and have a look at Ardmore.
The ruins of St. Declan’s cathedral date back to the 9th century A.D. Built of Old Red Sandstone, most of the masonry comprises coursed rubble walling but there
are also some fine examples of relief sculpture. I didn’t take a close look at
Ardmore round tower,
but these monuments give Ireland’s
architectural heritage its unique character.
Moving
on to Ardmore Bay, the tide was out and I had the opportunity to have a walk around
the sea shore. Here, the sandstone cliffs give way to glacial till, which forms
a low lying coastline, but some interesting rocks project from the sandy beach.
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| Devonian, Quaternary and recent sediments at Ardmore Bay |
I
had seen enough of the Old Red Sandstone, to appreciate its wide variety of
colours, textures and physical composition but, here, one of the fundamental principles
of geology came to mind – The Present is the Key to the Past.
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| Sand ripples at Ardmore Bay |
Rocky outcrops of
sandstone, more than 350 million years old and containing quartzite pebbles,
lie alongside similar unconsolidated sediments that have been washed up against
them by the flow of the last tide; however, what interested me most were not
the rocks but the various organisms that were growing on them – especially the
coral reefs.
I
had seen plenty of ancient corals preserved in the Carboniferous limestone but,
having never been close to a living reef before, this remains the most
memorable aspect of the natural history that I saw in Ireland.
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| Building stones in Dungarvan |
With
time moving on, I headed off to Co. Kilkenny – briefly stopping at Dungarvan,
to look at the bridge and the castle walls, and the Comeragh Mountains, where the Old Red Sandstone has been deeply scoured by ice to leave spectacular corries and waterfalls.
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| The Comeragh Mountains |
