Antique Late 19th C Photograph Of Pencil Drawing Gravestone Crypt Cemetery Frame

Description

This is what I believe to be a fairly unusual photograph of someone’s pencil drawing of a grave stone and crypt.
The grave stone is engraved with both the husband, who died 1872, and his wife, who died 1874.
The frame dates circa 1880s or 1890s. I believe it is original to the photograph, so this must have been photographed sometime in between.
The overall frame measures 12 1/2 inches wide x 14 1/2 inches high (31.7 cm x 36.8 cm). The mat (and frame back opening size) measure 10 inches wide x 12 inches high (25.4 cm x 30.5 cm). The photo itself measures 5 1/4 inches wide x 7 1/2 inches high (13.3 cm x 19 cm).
Oddly enough, someone had another mat made for this, though this mat is also probably 19th century. The original one that the photograph was attached to has decoration going around the exterior. Perhaps the person changed their mind and another mat was made. You can see this all in the individual photographs because it was all being held in with just a few nails.
The photo is both a gravestone and a crypt, since it is above ground.
It is engraved on top:
SACRED
TO
THE MEMORY OF
MATTHEUS CALLAGHAN,
WHO DIED 26 DECR 1872
AGED 86 YEARS,
ALSO
MARGARET HIS WIFE,
WHO DIED 12 JUNE 1874
AGED 84 YEARS,
At the bottom it reads:
WITHER THE HAND DISTURBS THIS STONE
I believe the last line was written as a warning to grave robbers, typically looking for old, valuable jewelry.
Both the photo and mat have foxing.
The frame has some scattered scratches and dings, but overall is in good condition.
It has its original bubbled and wavy glass. It has its original wood back.
I wish I knew the entire history of this!
It weighs a touch over 2 pounds (916 g).