Looking at Houghton le spring marriages she married a George Dunn and on the 1851 census, a margaret with a George living at Easington born 1806 it states she was born Blyth Northumberland is this your Margaret Carr?
I have looked on Family Search Bishops Trans. and on Houghton le Spring 1822-1830 page 201 is the marriage, which gives no clues to her parents and the marriage was by Banns.
JR