Todd & Meghan,
Both the Silvernale (Silbernagle) and Cookingham (Guckenheim) families had been in the Hudson Valley since the early 1700's and had long since lost their German identity. They were as likely to attend the dominant Dutch Reformed Church as any, and many descendants of early Palatine German families believed they were Dutch by 1850.
I have a large Silvernale file - who are you trying to identify?
Jim