Had a look at Mary and Jame’s marriage cert. Mary could have been born in Moycarkey and these records are online on the National Library website
http://registers.nli.ie/parishes/0248 and are also available on Roots Ireland which is a paying site.
I notice from the marriage certificate that James was approx 49 years old when they married. Could Mary have been younger, so perhaps you could extend your search for her to the late 1840s.
Hope this is of some assistance