The text is in Latin and is practically eroded beyond the point of being able to be read.
North side has the initials MA with shield which contains stars and half moon
South side letters PMG and shield which contains 3 bird outlines.
There are a number of transcriptions found for this inscription and and I have listed them here.
Sarcophagus of Patrick Gourlay, Town Clerk of Dundee, who died in 1667.
The Latin may be translated thus:-
"This Clerk was calm, and kind to persons all,
His goodness and his Candour were not small;
His life prov`d this unto the very End,
When trembling joints his Quill could not extend:
Painful and wise, meek, faithful, and his days
Closed in honour and immortal praise.
Son in his father's steps, and loving spouse,
Built up this Tomb for the dear Defunct's use
Collection of Epitaphs and Monumental Inscriptions Chiefly in Scotland (1834) Robert Monteith
Monumentum probi ac spectatæ integritatis viri,
This clerk was calm and kind, to persons all,
Claimant: Dr Gourlay, Magdalene Yard
The monument of a good man and of known worth, Mr Patrick Gourlay. Town Clerk of Dundee, most faithful in his transactions, who loosened from the corporeal chains of humanity, died 17th of the calends of January, in the year of the Lord 1667, and of his age 47; and Margaret Anderson his wife.
Source: The Book of the Howff, ©Libraries, Leisure and Culture Dundee, Local History Centre & is