Kilclooney More 3
Image by bogman

"the almost across the board 21 degree tilt of Irish portal tomb capstones"....

That's intriguing. Are there any theories about why that should be? Is there anywhere where I can read more?

As I understand it, the early spirit levels weren't very accurate.

:-)#

...I'll get my coats (it's very cold so I have two).

Kammer x

It is kind of curious, but I don't think anyone has really gone into it too much.

Usually the angle is produced by having the portal stones higher that the chamber walls

Sometimes they did this:

http://www.themodernantiquarian.com/browse.php?site_id=1376

and sometimes they used the shape of the capstone to do it:

http://www.themodernantiquarian.com/browse.php?site_id=912