I have just looked up the MI for Rushen plot ZF 15 in the IOMFS transcription.
This reads:
In Affectionate Remembrance/ of / THOMAS TURNBULL / who died September 6 1855 / aged 70 years / also of JANE TURNBULL / wife of the above named / who died May 9th 1863 / aged 45 years / WILLIAM TURNBULL / their son died December 1856 / aged 17 years / ALFRED TURNBULL / their son died April 21st 1873 / aged 24 years / also of CATHERINE COOK / their daughter died April 4th 1881 /aged 43 years.

As he was alive in 1881, it is possible that 1855 was misread (1885 perhaps?). Unfortunately there is no burial for either date.