Sacred to the memory of Jean beloved wife of Henry Earley Wyatt, died 1852 aged 47.
My flesh shall slumber under ground
Till the last trumpet's signal sound
Then burst my chains with sweet surprise
And in my Saviour's image rise.
(I don't think "signal" is right but it scans and I can't think what else it might be.)
Slate gravestones are rare in the South East.
P.S. It's "joyful" not "signal". I thought to google it on the off chance that it wasn't composed by the local schoolmaster and it turns out to be a verse from a hymn by Isaac Watts- which, in its turn, is a metrical version of Psalm XVII