Those who have read & understood my book From an Einstein Syndrome to the People (there’s even more in my International Journal of Physics 7-4-4) understand what I mean : as I’ve demonstrated the fireballs find their way to particulate places, where density is above average.
In past times before strong urban concentrations granitic areas & areas of effusive volcanism in general had few competitors. So the traditional dolmens are a product of the fireball impact ; read my short paper. The fireball is a cavitating object causing a deletion (delec‘hiañ) at impact ! Makes a cave out…
I argue there already was a feeling in traditional culture in Brittany that there was a particular tendency of fireballs to behave a certain way and that it imprinted the language into associating “finding” with “cavitation”.
(Yes, I feel that English is a good language to approach brezhoneg. It’s really obvious how the many Latin-rooted words coming from the French side are compressed in brezhoneg whereas there are true roots on the Anglo-Germanic side of the language and I even feel I have seen some proto-Finno-German – a mix dating from the Hanseatic period certainly, thou will see, in talvoudus : talo + hus, “valuable, useful”, what’s more valuable than a house ?)
Do note how in French we say “trouver” : Trou : hole ! Traverser – going through. So by putting trou and 1/3 of traverser together we get to a dolmen idea. In law “dol” is about lying, the dolmen lies to men !