Hi Diane,
Glenadagh is in Kilfian Parish and in the district of Crossmolina. I do have a few Morrisons that were entered in the Church of Ireland register (which covers a good amount of North Mayo, including Kilalla) LDS film # 897365
YEAR   MONTH   NAME   FATHER   SURNAME   MOTHER   SURNAME      RESIDENCE
1778   CONFIRM   And      Morrison            
1803   18-Jan   Jane   Jas   Morrison   Ann         Annagh,Kilfian
1803   13-Feb   Mary   John   Morrison   Eleanor         Rathmore
1804   CONFIRM   Eleanor      Morrison            
1807   none   MARR   Matt   Morrison   Mary   Shannon      Bglan,Keerglan
1807   Feb   MARR   John   Morrison   Mgt   Morrison      Glenadagh,Kilfian
1815   15-Jan   MARR   Matt   Morrison   Mary   Shannon      Glenadagh,Kilfian
This one, below, is the only Morrison entry in the Catholic Register:
YEAR   PAGE   MONTH   CHILD   FATHER   SURNAME   MOTHER   SURNAME
1807   IGI   28-Feb   MARRIAGE   Thomas   O'Donnell   Ann   Morrison
As far as port of departure goes I can't say for sure. People from Mayo left from Killala, Galway, Queenstown (Cobh) or even went to Scotland then possibly to English ports. In the 1840s there are very few ways to determine is found might have found the correct family in the Emigration papers because the passenger lists were so vague- first and last name, sometimes an age, where they were from-which would be listed as Ireland
. Not much else.
Diski