In the Irish civil registration index on the LDS Beta site, James Clancy & Bridget Conlon’s marriage is listed as registered in Manorhamilton Oct – Dec 1886, Volume 2, page 211.
There’s also a birth for a Hugh Clancy registered in Manorhamilton July – Sept 1893, Volume 2, page 188. You can get a photocopy of either cert from GRO Roscommon for 4 euros, provided you quote the place, year, quarter, volume and page number on the application form.
www.groireland.ie/That should give you the family’s townland, which in turn can be used to trace the line back.