Hi Beverely,
I can look up information for you over the next few days and would have today but saw your query too late in the evening.
You can look at the following website and get the best information available.
irishgenealogy.ie
In the page that opens, click on the Civil Records tab. On page that follows. only type in the surname O'Mahony Do not use a forename. leave blank. In the date range, use 1862 - 1900. in County use Cork. In Civil Registration use Schull with this spelling. Click on all options in Births, Marriages & Deaths. You will get a large range of O'Mahony's this way and the best way then is to type in a forename such as Thomas in the Search box and click on search again. If using any other searches use the Townland name Cappanacallee with this spelling. It will not help the search but you can use it to help identify the correct family
One last few words for tonight, for speedier response, direct any further queries directly to me at frankfahy054@gmail.com as it saves a lot of time for me. I am a volunteer with Ireland XO for the West Cork area. Frank Fahy