Merlin's tomb

Which of these do you think makes the best tomb for Merlin? You might like to bear in mind that he was supposedly trapped forever in a grotte. The top picture is so-called Merlin's Tomb from the forest of Paimpont, heavily marketed as the Brocéliande of Arthurian legend (for no very good reason). It is in fact the remains of a neolithic dolmen. There are no caves in that forest, so nothing can be made to fit in the way they've managed with the Valley of No Return (nice valley, shame it was once publicised somewhere else entirely until a factory was built there). The second photo shows a veritable grotto, tucked under the rim of Mont Dol near Dol-de-Bretagne. This area on the eastern edge of Brittany was once covered by a great forest. And wait a minute! Wasn't Brocéliande supposed to be near the sea and in the Marches de Bretagne?
Of course Brocéliande is a literary creation, first mentioned by Wace in the 12th century Roman de Rou. He was a Norman with Plantagenet patrons, just up the road from Dol and Combourg, once in that eastern forest. He said he visited the forest himself. And Geoffrey of Monmouth who started the whole Arthur saga in its recognisible form today may also have ties with Dol. But no-one could possible doubt all the hype surrounding the Arthurian forest of Paimpont - could they?