My GGGrandfather, Kasimir Heinrich Fehring, was from Hanover also. He married Anna Gertrude Lampe sometime around 1860 which is also the time they immigrated to this country. They are living in Clinton Co IA on the 1860 census. They have 8 kids which includes a daughter named Maria Adelhaid (Alice). Heinrich and your Adelhaid could be related as they come from the same area.