Hi Katie,
I have checked the Newmarket baptism records for you and found 4 records for a Johanna Collins born in Newmarket all between 1857 and 1859.
The 1881 marriage record states that both James Herlihy and Johanna were from Kanturk.
When checking the origina marriage record on Irishgenealogy I noticed her fathers name is listed as Daniel
Collins from the address Greenane Kanturk, see https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_re…
According to the same marriage record Johanna was a minor meaning she was under 21 years old in 1881 at the time of her marriage, the only matching record for the area I can find is the baptism of Johanna Collins on the 20th October 1866 in Meelin county Cork, father Daniel Collins and mother Mary Shine, the address Gooseberry Hill, these records can be found on www.rootsireland.ie a subscription site
Hope this helps,
Anne Marie