Looking for Gill Family of Concord Massachusetts

Hello,
I'm looking for information to find more of my Gill ancestors. My 5th great grandfather is Silas Gill, he was born,1759 poss. in Concord, MA and died 4 Oct 1804 in Concord. His wife was Sarah (?)Gill b. 17 Jun 1754 in Salisbury, MA and died 24 Feb 1804 in Hingham, MA. I have no maiden name for Sarah, and no information on either of their parentage.

They had 6 children

i. Silas Jr. 1782-
ii. Otis 1786-
iii. Sarah "Sally" 1790-1867 (my 4th g grandmother)
iv. Hannah 1792-
v. Anna 1796 -1872
vi. Mary 1800 -

That's all I have on them...if anyone can find the parents of Silas Sr., and his wife (plus her maiden name) that would be greatly appreciated.
Vanessa