I too have Jacob and Cornelius Krom's in my family line. It goes as follows: Willem Gijsbert Crom Krom m Maycken Hendrickson in the Netherlands on April 7, 1645. They had: Lysbet Willmse, Bysbert Willems, and Geerhe Willemsen.
Gysbert m Geertie Van Fleet in the Town of Rochester, Ulster Co., NY They had Catherine, Willem, Mayken, Dirk and Hendrick.
Dirk M Eva De La Montagne and they had Willem, Gysbert, Cornelius, Geerten, Johannes, Elehonora, and Hendrick.
Gysbert m Catrina Osterhout and had Jacubus.
Jacubus m Maria Polly Osterhout and had Jacob.
And the list goes on. The time frame her is from about 1629-1801.
The family began in the Netherlands, then came to America in about the 1660's.
If you would like more info, E-mail me at Emaco241@aol.com Susan