Hello, thanks for the quick reply! 

 The birthday I have is July 11, the year 1880-1883. She had an older sister named Susan born about July 1865, who married a man with the surname Saxe. Here is my transcription of the paper I have:
 "In Her Majesty's High Court of Justice, Ireland
          Probate and Matrimonial Division
                  (Probate)
    Before the Right Honourable Robert R. Warren the Judge sitting in 
    open Court at the Four Courts, Dublin The 23 day of February 1891                        
    In the Goods of}          On reading motion paper filed the
    Patrick Hegarty}     
         Deceased  }          13 day of February 1891 copy affidavit 
___________________}
 of  Mary Hegarty and copy exhibit marked "A" therein referred to copy 
affidavit of John Lynch and copy affidavit of George Dillon all filed 
the 13 day of February 1891. And on leaving Mr. Henry, Counsel for 
Mary Hegarty, It is ordered by the Court that notice of this motion 
be inserted as an advertisement in the Coleraine Constitution 
newspaper once shall be deemed good service of such notice on Denis 
Hegarty, Susan Saxe otherwise Hegarty, Martha Hegarty, Daniel 
Hegarty, and Catherine Hegarty all in said affidavit of Mary Hegarty 
referred to.
J.E. Proctor         }
   Solicitor           }
47 Rutland Sqre }
____________  }