The Will of William Selby was executed August 13, 1761, and probated March 4, 1762.
Beneficiaries under the will include his second wife Martha, daughter Sarah Martin, grandsons John Selby Martin, George Martin, James Martin, Chesed Purnell, Lemuel Purnell and William Purnell and Mary Marchment. His wife Martha and son-in-law Thomas Martin are named joint executors.
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]