poulnabrone dolmen, a portal tomb in the burren in ireland

2900 4200 and archaeologist back ballyvaughan between blue buried burren cairn capstone carran celtic ceremony chamber clare cloud county crevices dates dating dolmen dramatic excavation field flat found grass green grykes hole ireland karstic laid landscape large like limestone low megalithic monument mound natural nature neolithic parish pavement period popular portal portico poulnabrone probably quern remains ritual rocks site sky slab slender sorrows south stone stones study supported tabular the tomb two uncremated under upright were