I cannot find this Matthew either--but--in 1820, 1830, & 1840 there is a Matthew Floyd as Head of Household in Northhampton, VA. The 1830 has one that could be your Matthew--age wise. I haven't looked at a map, but with counties changing as they did , it could be that the county changed rather than them moving. I went through all of 1850 Floyds in VA and not a single one fit. According to the 1860 census he was b. 1820, but either was still single in 1850 or married to somone other than Margaret, as her birthdate shows as 1835. Of course it wasn't unusual to marry at 15 back then-- anyhow I can't find them. Sorry.