There is a 'book' in the British Natural History Museum, that is the earliest written history of the Isles now called Britain. It speaks of the 'science'/'religion¿' of those 'Atlanteans¿' once known as the Fair Folk (fairies) who were fair skinned very tall thin silver-blonde people washed up on the shores of what is now Devon and Cornwall, from Isles beyond Scilly out in the ocean. They were by those accounts well founded in 'science' and had astonishing 'pictures'/maps, as seen from edge of atmosphere. The book is probably very difficult to get permission to view now, but from my memory it was called -coelura lingus- and it comes to mind from your post because of the views of geoglyphs. There was also mention of a burning liquid that gave light but little heat that was used in ceremonies above ley-line-dragons (hills at ley nodes) called telluric energy¿
It was thought that the 'Drowned Lands' between north Cornwall, South Wales and S.E.Eire were also part of their lost land, but that I never read further has haunted me when I am reminded of that studious summer.