The hunt for the Morvil Scottish erratic.....

Today, on a fine sunny winters day, we went up into the mountains on a hunt for the "Scottish erratic"............

Quote:  Erratic clasts, including gneissic rocks from northern Britain, for example at Morvil Farm [SN 037 307], Puncheston, confirm an Irish Sea provenance.

Reference: Burt, C., Aspden, J., Davies, J., Hall, M., Schofield, D., Sheppard, T., Waters, R., Wilby, P., Williams, M. (2012). Geology of the Fishguard district: a brief explanation of the geological map Sheet 210 Fishguard. British Geological Survey.

https://webapps.bgs.ac.uk/memoirs/docs/B06909.html

As far as I know, there are no gneissic rocks in Pembrokeshire, so to find an erratic of Lewisian gneiss from the island of Lewis would be quite something.  Mind you, there are also gneissic rocks on Skye, Iona and the NW Scottish mainland -- including some areas near the Irish Sea Glacier ice shed, from which there was a southward flow of ice.  There vare some related rocks in Ireland as well.  

The six-figure grid reference given by Burt et al is not adequate, and after hunting around Morvil Farm, along the road and in the adjacent paddocks today I found plenty of dolerite erratics, but nothing made of gneiss......  I might go and take another look when the weather is warmer.

To find a gneissic erratic here, at an altitude of 210m high up in the foothills of Mynydd Preseli, would be almost as exciting as finding the "shelly drift" high up (c 400 m asl) above the North Wales coast at Moel Tryfan.....

https://brian-mountainman.blogspot.com/2014/09/the-shelly-sands-and-gravels-at-moel.html