Roger, are your Nicholsons Irish or Scottish? My gggm was Ellen Nicholson Waldron, b in Ireland,(1829) married in Kilbirnie, Scotland in 1844. With her husband, Wm Waldron,she resided in Normanby, Grey Co. I found an Alexander Nicholson on the 1880 Atlas for Egremont, Grey Co. Alexander was born 1823, Scotland, and settled in Grey Co.1855. He owned Concession Xlll, Lot 13 (100 acres).
I found another Alexander Nickelson on familysearch.org in Bruce Co. who was in the right age range, but would put him in a different county one year later.
Anyway, Alexander (Egremont) would be the right age to be my gggm Ellen's sibling, and I wondered if this was your family? My Waldrons emigrated from Scotland around 1854, I think.They were related to the Spicers, Coutts, Robbies, Duncans, McCrory. Thanks, M.E. Corcoran at timedoc@earthlink.net