I have just started to research this family trying to make a connection to possible siblings or cousins (these two were not married)
Lorinda Morrison b: York/PA ~1814
Jonathan Morrison b: PA ~1811 or 1813
This book pg 36 discusses one line, including Michael Morrisonhttp://books.google.com/books?id=tz54aBcpZUQC&printsec=f...
I try to recruit Morrison men to join the Morrison DNA project if you known any please ask them to consider it -- see if you recognize names/locations on the "Results" page here:http://www.geneticousins.com/morrison
If we can connect with DNA then the lack of records need not be a brick wall in the search.