I have found a resource which gives you a load of details on Thomas Gerard 1608-1673. He was born at New Hall, Lancashire, England.He immigrated to Maryland in 1638, returned to England and settled on Mattapany, St. Clement's manor, Maryland 1642.He was first married to Susannah Snowe then to Rose, widow of John Tucker.He did have a daughter Susannah who married Robert Slye first, then John Coode.
The source which is based totally on research and gives many more details of this fellow is:
"Robert Cole's World", published in 1991.I found it on Amazon.com, used and there are more copies available.The book is invaluable in giving real insight to how our ancestors of Maryland truly lived.
If you wish, would send you the mini-bio this book has on him, but there is a lot more in the body of the book.