Her name has been spelled both “Checkly” and “Checkley”.
There is also a Charles Checkley (born in Cork) that moved to the Fitzroy area in 1836, who married an American named Elizabeth Evoy. They had 6 sons and 1 daughter born between 1842-1894, and lived 1811-1894 (Charles) and 1819-1894 (Elizabeth). The homes built and sold in the area went to the Curtis, Checkley, Boyle, Ring and some other families, so they may be related to Mary as well. If he is related, he emigrated to Canada in 1836, to Lot 2, Con. 3, S1/2. It should also be mentioned that it appears that his widowed mother (then age 70, so born around 1782) is also staying with them, and was also born in Cork. These all may be relatives Mary.
Garvin has her name as Mary Ann Checkley.