Hi Josh: I also am trying to track down my great grandmother who lived in Cornwall the same time frame you are looking at.Margaret Pond Brennan, I know is buried in Martintown, Ontario, part of Glengarry County & Stormont. Apparently she lived in Cornwall.
Margaret was married to John King & had 4 children listed in 1901 Census for Ontario, Canada. Trouble is my grandmother had flown the coup by then and that lady listed is wife #2.My grandmother was Sophia King m Paul Benoit.
A good site I found today is www.cornwallgenes.com and I wish you luck with it.It helped me out quite a bit.
I am wondering about a Lemarre I seen on the site and you are connecting Pond with Lemarre.Will let you know if I find anything you can use.Barb