Oh... I saw that but I was in 1st person mode and thought I was supposed to find more of those around Ahra Pahts, which I didn't do for two contradicting reasons: One is that Ahra Pahts is a really big place if I did have to look all around, and second is I thought all shards were strictly contained inside the walls, so I ended up thinking that the clue was the Ahra Pahts map itself, at which point I left the shard to save my sanity.
But in 3rd person the clue is much more obvious. Thanks Annabelle!
EDIT: Where do I find the latest list of Shells?
can't find a logical pattern. moving on...