Longworth Family of Sharrocks Farm, Horwich

I didn't see this monumental inscription when looking in the churchyard, but it's recorded in the MIs book at Bolton Archives (B929.5B).  It must be in one of the blue sections below:-

Plan of Horwich Churchyard

Gravestone of William and Mary Longworth of Sharrocks

Sacred
to the memory
of WILLIAM son of WILLIAM
and Mary LONGWORTH of Horwich who
departed this life August 16th 1812
aged 22 months
also THOMAS son of the above nam'd
WILLIAM and MARY LONGWORTH who de
parted this life May 4th 1829 aged
21 years

Why should we mourn departing friends
or shake at death's alarms
tis but the voice that Jesus sends
to call them to his arms

also JAMES, their son who depart
ed this life March 23rd 1840 aged
35 years

My parents dear, grieve not for me
since Christ my saviour's set me free
he has redeemed my should from sin
and now I'm with my lord shut in

also the above named MARY LONGWORTH
of Sharrocks-Farm, who
departed this life May 31st 1841
aged 63 years
also WILLIAM her husband who
departed this life Nov 15th 1848
aged 69 years
3 breadths from the north side of this stone
belongs to WILLIAM LONGWORTH