Small/Alter Family

I've found an interesting reference for the Alter Family. Mary Alter was the wife of William Small, mother of Alfred Small, who was father of Leslie Earl Small. There are two volumes of "The Groff Book" which records the history of the Alter Family back to their immigration from Rotterdam around 1750. John (Johann) Heinrich Alter came from Rotterdam and initially settled in Lancaster County, PA before moving to Cumberland County, PA, where the town Alter's Mill was later established. The 1886 History of Cumberland and Adams County has information on the Alter Family in the 1800s.