Hello Melanie,
if you are talking about Hartwarden, parish of Rodenkirchen, there are no
microfilms for the years around 1868.
Church books can be consulted at the parish in Rodenkirchen or at the
Oldenburg State Archive, Damm 43, Oldenburg.
You could also write to
Hartmut von Haefen
Wacholderweg 30
27476 Cuxhaven
By the way, if the only daughter inherited a farm, her husband (and the
children) frequently took the family name of the wife.
Regards
Gerold Diers (Oldenburg Genealogical Society)