I was very gald to receive your query about Mary Catherine. She may be one of the missing children on John W. Adams. I base this on the fact that Talitha Frances is not a very common name, but several members of our family have it. I wonder if Mary Catherine was an older sister that we don't have.
Please email me at firstname.lastname@example.org and I will send you the information I have. Do you have dates, places, etc. for Mary Catherine and her family and descendants. I would like very much to have them so that we can see if we can match up somehow, someday.