Valentia Island, a set on Flickr.
Our last day - Valentia Island
Friday 20 May 2011
Sunday 1 May 2011
Last day - Tetrapods and myriapods
The final day was all on Valentia Island, now with a handy bridge across from Portmagee. We started off at the old Valentia slate quarry at Dohilla where smooth slabs of astonishing size were produced in the past: used for billiard tables and shelving in particular. These are underground quarries but were closed in 1911 because of foreign competition - from Wales - though there has been some recent interest and we could see modern machinery down in the quarry. Part of the main quarry approach has been converted into a grotto with a statue of Our Lady and Bernadette highup on the cliff. Sadly we didn't know if they were lifesize or no, so no good for scale.
From here we went down to the Tetrapod trackway site, also at Dohilla. This is one of the earliest records in the world of primitive amphibian trackways and was discovered in 1992 by Iwan Stossel, a geology student from Zurich, and published in 1995. Dating of associated volcanic rocks places this at 385 Ma.
The footprints don't show any detail and are likely to be underprints but even so give a lot of information about the size and and movement of the animal. One shows body drag and another, tail drag. They've been deformed by tectonic stress but strain analysis shows the original body length was around 1m.
There's a good interpretation board and the access is easy from the designated car park via a pathway down to the top of the low cliff.
Lunch was in Knights Town - built in the 19th Century for the quarries and, as far as mine went at least, was another bowl of delicious chowder eaten on a roof terrace overlooking the harbour. After a diversion to see the Altazamuth Stone (and some debate about why it isn't Altazimuth) and a walk to the museum to get some booklets about the trackway (if shut ring the number on the door!) we went back round to Trawagwinnaun Bay on the way to Cromwell Lighthouse to check out a wide dolerite dyke, and then below the lighthouse to see the Valentia Slate Fm which has a number of trackways of Diplichnites - must have been about the size of a largish centipede!
As a finale we went over to the other end of the island to Telegraph Field where the transatlantic cables came ashore - a fascinating monument has cross sections of the actual cables embedded and the field is also the site of one of the last dancing platforms.... where comely maidens danced at the crossroad... Bettie and Jan obliged! Cups of tea and scones nearby completed a really super day
With an early start for the 250 mile drive back to Dublin in the morning some of us weren't planning on making a night of it but we still found time to go down to the pub for a last Guinness
From here we went down to the Tetrapod trackway site, also at Dohilla. This is one of the earliest records in the world of primitive amphibian trackways and was discovered in 1992 by Iwan Stossel, a geology student from Zurich, and published in 1995. Dating of associated volcanic rocks places this at 385 Ma.
The footprints don't show any detail and are likely to be underprints but even so give a lot of information about the size and and movement of the animal. One shows body drag and another, tail drag. They've been deformed by tectonic stress but strain analysis shows the original body length was around 1m.
There's a good interpretation board and the access is easy from the designated car park via a pathway down to the top of the low cliff.
Lunch was in Knights Town - built in the 19th Century for the quarries and, as far as mine went at least, was another bowl of delicious chowder eaten on a roof terrace overlooking the harbour. After a diversion to see the Altazamuth Stone (and some debate about why it isn't Altazimuth) and a walk to the museum to get some booklets about the trackway (if shut ring the number on the door!) we went back round to Trawagwinnaun Bay on the way to Cromwell Lighthouse to check out a wide dolerite dyke, and then below the lighthouse to see the Valentia Slate Fm which has a number of trackways of Diplichnites - must have been about the size of a largish centipede!
As a finale we went over to the other end of the island to Telegraph Field where the transatlantic cables came ashore - a fascinating monument has cross sections of the actual cables embedded and the field is also the site of one of the last dancing platforms.... where comely maidens danced at the crossroad... Bettie and Jan obliged! Cups of tea and scones nearby completed a really super day
With an early start for the 250 mile drive back to Dublin in the morning some of us weren't planning on making a night of it but we still found time to go down to the pub for a last Guinness
Saturday 30 April 2011
Dingle to Portmagee
Dingle to Portmagee, a set on Flickr.
South coast of Dingle, then Gap of Dunloe on the Iveragh Peninsula
Macgillicuddie's Reeks and Portmagee
The second half of the trip is based at Portmagee on the north coast of the Iveragh Peninsula opposite Valentia Island so to get there, although it was only just over the water from Dingle, we had to go back up the Dingle 'finger' and down the Iveragh 'finger' with various diversions such as the Ring of Kerry and Kate Kearney's cottage on the way. We were planning to meet Ken's wife Bettie, who is also a geologist, and a colleague, Pat Meere who is a structural geologist, at KK's cottage at lunchtime so there was time for a potter along the coast during the morning.
A wander outside before breakfast showed preparations for a music festival in Dingle that weekend but we turned our backs on the fleshpots, packed up the cars and headed off to Kilmurry Bay where I'm afraid the boulder beach defeated me (and a few others) but most went on down to have a look at the coastal section at the eastern side where large scale, cross-stratified pinky-red aeolian sandstones are exposed in the cliffs. Ken is a brilliant leader though and had a road cut in his back pocket where we stopped to look at something similar: there were steep avalanche faces and, amazingly, Cruziana tracks where beasties had scuttled across the face of the dunes. Trevor the climber came into his own here and obligingly scuttled up the face of the cutting and hung on with his fingernails while we took photos with 'Trevor for scale'. Oh and as first spotter of a trace I got bought a Guinness that night by Ken!
Several road cuts with well planned laybys opposite allowed us to have a good look at the absolutely beautiful Inch conglomerate and the overlying Lough Slat conglomerate. The Inch conglomerate is the result of erosion of high grade metamorphic rocks and contains stunning mica schist clasts. The metamorphoic rocks were thrust upwards along the Dingle Bay lineament, forming a ridge which was eroded, producing extensive fanglomerates. The Lough Slat conglomerate is totally different with white vein quartz and red jasper pebbles and derived from the opposite direction and unconformable on the Loch Inch C.
On then, past Inch spit (always a windy place to bathe apparently but good for surfing) to the Iveragh Peninsula and soon we saw an awesome cleft in the hills ahead of us - this is the Gap of Dunloe which we were going to explore. We met up with Bettie and Pat, had the local version of chowder in KK's C and then headed on up the valley. The road is 'recommended' not for cars as the local attraction is pony and trap drives up and back but there still seemed to be a lot of cars which we rather objected to as we were on shanks pony. The exception was a wedding group who were in high spirits - we felt they deserved a good place for their photos!
It is a very long road..... and rather hard under foot.... and I think the best bits were near the start really where we saw good faulting and thrusting and signs of stress in these northward thrust rocks. The Gap cuts neatly through, perpendicular to the direction of thrusting and is a good cross section route. Lovely lakes with water lilies coming into leaf and the grass was speckled with butterwort in flower,
On then to Portmagee. We needed to get a bottle of whisky to give to Ken that evening and had, stupidly, forgotten it at the supermarket stop earlier so had to drop out and search the small shops along the way. Unfortunately Tony, who was on his motorbike, stopped too to get fuel and we went on without him! Then it bagan to rain - only rain of the trip... and we had a plaintive phone call from Tony. Well we set him on his way, and went on to the hostel to get the others settled in (they had more or less done it) and then went back to meet our lost sheep who by this time had headed on over the bridge onto the island.. NO Tony! We got him back and thought he was following us but it was mere coincidence so there was a sort of Keystone Kops chase up and down Portmagee High Street before we finally got him!
Nice after that to have a proper sit down restaurant meal to look forward to - bit hard on the pocket mind, but very much enjoyed the taster plate of local sausages as well as our main course.
Tomorrow - the tetrapod tracks!
A wander outside before breakfast showed preparations for a music festival in Dingle that weekend but we turned our backs on the fleshpots, packed up the cars and headed off to Kilmurry Bay where I'm afraid the boulder beach defeated me (and a few others) but most went on down to have a look at the coastal section at the eastern side where large scale, cross-stratified pinky-red aeolian sandstones are exposed in the cliffs. Ken is a brilliant leader though and had a road cut in his back pocket where we stopped to look at something similar: there were steep avalanche faces and, amazingly, Cruziana tracks where beasties had scuttled across the face of the dunes. Trevor the climber came into his own here and obligingly scuttled up the face of the cutting and hung on with his fingernails while we took photos with 'Trevor for scale'. Oh and as first spotter of a trace I got bought a Guinness that night by Ken!
Several road cuts with well planned laybys opposite allowed us to have a good look at the absolutely beautiful Inch conglomerate and the overlying Lough Slat conglomerate. The Inch conglomerate is the result of erosion of high grade metamorphic rocks and contains stunning mica schist clasts. The metamorphoic rocks were thrust upwards along the Dingle Bay lineament, forming a ridge which was eroded, producing extensive fanglomerates. The Lough Slat conglomerate is totally different with white vein quartz and red jasper pebbles and derived from the opposite direction and unconformable on the Loch Inch C.
On then, past Inch spit (always a windy place to bathe apparently but good for surfing) to the Iveragh Peninsula and soon we saw an awesome cleft in the hills ahead of us - this is the Gap of Dunloe which we were going to explore. We met up with Bettie and Pat, had the local version of chowder in KK's C and then headed on up the valley. The road is 'recommended' not for cars as the local attraction is pony and trap drives up and back but there still seemed to be a lot of cars which we rather objected to as we were on shanks pony. The exception was a wedding group who were in high spirits - we felt they deserved a good place for their photos!
It is a very long road..... and rather hard under foot.... and I think the best bits were near the start really where we saw good faulting and thrusting and signs of stress in these northward thrust rocks. The Gap cuts neatly through, perpendicular to the direction of thrusting and is a good cross section route. Lovely lakes with water lilies coming into leaf and the grass was speckled with butterwort in flower,
On then to Portmagee. We needed to get a bottle of whisky to give to Ken that evening and had, stupidly, forgotten it at the supermarket stop earlier so had to drop out and search the small shops along the way. Unfortunately Tony, who was on his motorbike, stopped too to get fuel and we went on without him! Then it bagan to rain - only rain of the trip... and we had a plaintive phone call from Tony. Well we set him on his way, and went on to the hostel to get the others settled in (they had more or less done it) and then went back to meet our lost sheep who by this time had headed on over the bridge onto the island.. NO Tony! We got him back and thought he was following us but it was mere coincidence so there was a sort of Keystone Kops chase up and down Portmagee High Street before we finally got him!
Nice after that to have a proper sit down restaurant meal to look forward to - bit hard on the pocket mind, but very much enjoyed the taster plate of local sausages as well as our main course.
Tomorrow - the tetrapod tracks!
Friday 29 April 2011
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