The Will of William Selby was executed August 13, 1761, and probated March 4, 1762. Thomas Martin was named joint executor under the will. His wife Sarah Selby Martin and sons John Selby Martin, George Martin and James Martin, identified as grandsons of William Selby, were named beneficiaries. Reference is also made to a tract of land, then owned by William Selby, called "Middle", as being adjacent to "the land and plantation whereon Thomas Martin now lives".
A copy of the Will Book is available at the Maryland State Archives website:
http://guide.mdsa.net/series.cfm?action=viewSeries&ID=s538
[1760-1762 DD 1 Book 31, pp. 546-47 - msa_s538_000046.pdf, pp.546-547]