Mary P Powell 1937 - 1906.
Have just gone back to the source, which I had found on freepages.genealogy.rootsweb.ancestry.com but for some reason Homestead Cemetery doesn't appear there now!!

However had made a note at the time querying the P, as this is Mary Ann Powell mother to James W Jones and mother in law to Ellen A Jones, who died in Steubenville, Ohio.
Perhaps a transcription error from the gravestone?
I should have noted that error when I posted it. Sorry

You may have noted that the Powell children all started off with a single given name at birth, but nearly all give themselves a middle name when they are adults . My Henry became Henry Theophilus when he arrived in Australia. John has M as a middle initial when he gets to USA. William adds James in the UK census and so on........
Dash