Civil Registration was established in 1875 for the whole of Germany after its unification.
From 1 January 1876 every town of any size had to have a Standesamt (registry office) of its own, and these were
grouped under a local Standesamt to which they were responsible.
Every city of any size possesses its own archives and every Province or Land its Staatsarchiv.
Generally speaking, the southern kingdoms were Catholic and the northern Protestant and the Protestants were
divided between Lutheran and Reformed churches.
The area of your search needs to be narrowed. Searching in Halle, Germany is like searching in Kentucky, U.S.A.
A search of Gerhard's immigration records produced a passenger list but, it does not give a home town. At this point,
you need to locate Gerhard.
On the passenger list C.I.C. Bonegilla is given as his destination. You will find a very informative article about this place
at the following web address http://www.migrationheritage.nsw.gov.au/exhibitions/somuchsky/.
Please let me know if I can be of further assistance.