This coat of arms belongs to the Moodie family of Breckness or Melsetter and lies in the old section of Warbeth Cemetery, Stromness, Orkney. The coat of arms has chevron with a 'castle/beacon' to the top left and two pheons points upwards and a hunting horn in chief. The date '1734' has the initials 'IM' above it to the left and '?M' to the right.
A complete model of the monument it has fallen from can be found here: https://sketchfab.com/models/d9fe8769eb83400199ab6546147005b3
The detail is difficult to appreaciate with the texture and is much clearer in matcap mode.