LOCK, Sam[ue]l, s. Sam[ue]l, [born] Dec. 18, 1748. PR [PR=Rev. Samuel Cooke's Abstract of Births, Deaths and Marriages]
The Arlington VRs (p. 32) give the birth of another child to Samuel on Dec. 15, 1748, and the compiler has filled in the given name Samuel. The death records show that on 15 Dec 1748 an unnamed child was still born. It appears that the Samuel on 18 Dec survived. Twins whose births are separated by three days?
