Dear Listers,      Could any of you explain what the letter's A R P and the number's under them mean?   I have an Ordinance Survey Map (c1846) of a townland in Wexford.  I found my ancestor's name on Griffith's Val, giving the letters ARP with numbers refering to the location of his property on the OS map.   I haven't a clue how to find his land.      Thank you,      Beth McBride      Illinois