Yes, I see what you mean. all I can say is that these are burial records, the book I have is monumental inscriptions only. There were 2 distinct burial grounds here - St David's churchyard (founded 1720) and the Ramshorn Burying Ground (founded 1780).
The "Baillie's" may have been a piece of common (or public) ground, probably in the Ramshorn ground that was set aside for children (how old was your John Menzie in 1840?) or for indigent family members of baillies of Glasgow? Perhaps purchased for that purpose by a bequest? Who knows.
The records used to be kept by Glasgow City Archives (previously Strathclyde Regional Archives) and may still be there (with copies at Edinburgh) but because of the current situation, the Archives are closed. There is also an old book, possibly there is a copy in the City Archives at the Mitchell Library, called "Story of the Ramshorn Churchyard" by Rev E. Sherwood Gunson, published 1910. It may have some useful information.
I wonder what "2 off 76" means against Robt Cooper? Interesting that there is no Robert Cooper in the index for the MI's. "W&L" stands for Wylie & Lochhead, undertakers.