From early records of Lunenburg County which can be seen at:
http://freepages.genealogy.rootsweb.ancestry.com/~downeast/1...William Gerber, married Matilda Robar in 1862. Also the same site lists birth of their son
Zenas Gerber born June 26, 1869.
The marriage of a Zenas Garber, son of William and Matilda, to Laura West in 1904 from the NS Archives site confirms that Zenas Garber and Zenas Gerber are one and the same--the name like so many of the German names has a very "fluid" past when it comes to spelling.