"I've learned here not to expose my crazy ideas to group criticism"

Since when? (-:

And while we're on

http://www.themodernantiquarian.com/post/43633
"This fragment of a Rock Art panel was found outside 85 Harpers Lane, a quarter mile to the west, and is 'cup and ring art'"

What makes you think that?
Without context it just looks like a lump of dressed stone taken from somewhere else and incorporated into a modern wall. We have a number of such stones where I live, they were taken from sources as diverse as ruined churches, mine engine houses and mediaeval alum works buildings.

And finally
What is your definition of earthfast?

shine on, you waggish waller