There was a Mary Smith (prob. b abt 1790) who married a James Gurnee and had several children. Her father Edward's probate file in 1842 mentioned only her children that stayed in Rockland: Levi, Frances, Rebecca and Anna. Her children that followed their "father out west" were cut out of the will. Many people from Rockland county went to Wayne county NY, often before going even further "west".
I tend to think that the previously mentioned Mary & James were the same Mary (age 63) & James F Gurnee (66) in the 1850 census for Huron, Wayne co, NY w/ John Gurnee (20) and Mary Conklin (18) and David Conklin (8). I assume that John was a son and the Conklins were grandchildren (dau Anna had married a John J Conklin). I once corresponded w/ another researcher whose Michigan ancestors decended from Anna & John Conklin).