Wednesday 15 April 2015

Co. Kerry - Valentia Island


A view from Valentia slate mine

I must have driven more than 350 km to get from Dublin to Valentia Island, and it is not surprising that an audit of the County Geological Sites in Co. Kerry has not yet been completed; the route around the coastline here is an absolute maze and, wherever you go, you seem to be surrounded by strongly folded rocks.

Now that I had visited two fine stone built ancient monuments, to take photographs that were suitable for the Dublin Stone Show, my attention again turned to my job to survey some of the building stone quarries that had been identified as County Geological Sites.


General views at Valentia slate mine

With the quarry faces of working quarries often changing, when these are highlighted as having conservation interests, it is important to identify and confirm the boundaries of such sites, and to assess their impact on the surrounding landscape. Having opened in 1815 and, employing 500 men in its heyday, the surface activities have created a scar on the landscape - but it is an important part of Ireland’s Geoheritage and the Grotto is an attraction for general tourists here.


The Grotto at Valentia slate mine

At Valentia Island, the dark grey Devonian slate found here contrasts strongly, in colour, with similar rocks from the Old Red Sandstone that are often found in the counties of Devon and Cornwall, in England, and it was extensively used for roofing some of the great municipal buildings of London, in the 19th century. 


The Valentia Island Tetrapod Trackway

Another reason for visiting Valentia Island is to see the Tetrapod Trackway, the oldest reliably dated evidence of amphibians walking on land. The ripple marked bedding plane of the Old Red Sandstone, on which they are found, was wet and the overcast conditions rendered them difficult to see, but I was very pleased to find yet another interesting little bit of Ireland’s geological history.