Craigton Cemetery - Glasgow

[heatherrr]

I've found some relatives buried in Craigton Cemetery - judging by the burial records, I'm sure it says section U. I don't have the original lair record because I don't know when it was purchased, but the deaths I know of begin around 1891.
Looking at the map/layout for Craigton there doesn't seem to be a section U.
Has anyone else came across this? Is U a newer section, not noted on the layouts? Or could I be reading wrong?
Attached a snippet of the Lair/Section.
Thanks.

[CaroleW]

Could U stand for Unmarked?