Fact Five: Isotope analysis has proved that the Penywyrlod long cairn has 5,700 year old human teeth buried under it.

The article in the American Journal of Physical Anthropology in July 2017 provided the isotope analysis of enamel from teeth under the long cairn that they could date with 70 year accuracy to between 5,770 and 5,630 years ago. So indisputably early Neolithic.

If 26 miles away, why not under Garn Goch’s similar long cairn? Don’t we deserve to find out? They’ve done the excavations in England and at Penywyrlod, so why not at Garn Goch?

Isn't that convincing evidence?

But then that doesn’t prove the surrounding stones were Neolithic. They could be Iron Age walls that happened to be built around a Neolithic cairn, but some surprising numbers make that highly unlikely. See Fact Six.