Individual Details

Ancestry.com: "London, England, Baptisms, Marriages & Burials, 1538-1812"
Baptisms at Hillingdon, Uxbridge St Margaret
There is what appears to be an incomplete entry 18 Aug 1634. The child is Christopher - the father's abbreviated first name, may indeed be Wm and the surname does look much like Coomestock in the other entries - it has been indexed as "Cumsters" which it certainly isn't. There is definitely a later entry for a Christopher Comstock - perhaps this child died as an infant.

Christen	18 Aug 1634	Saint Margaret of Uxbridge, Middlesex, England
Death	Bef May 1636

Father	WILLIAM COMSTOCK (1595 - 1683)
Mother	ELIZABETH Cock (1608 - 1665)
Sibling	Daniel Comstock (1624 - 1683)
Sibling	John Comstock (1626 - 1680)
Sibling	SAMUEL COMSTOCK (1629 - 1657)
Sibling	Elizabeth Comstock (1631 - 1659)
Sibling	Christopher Comstock (1636 - 1702)