There may be a record in the clerk's office, but that is pretty early. But at that date, almost everyone in Turner County was a homesteader. If Joseph and/or Agnes were children of homesteaders, you might check the BLM records for homesteaders. In addition, there are homestead plat diagrams for the various ections naming owners of the various parcels. These are in the county records, probably the clerk's office, but don't overlook the assessor's office. I have a copy of one of these for a different section and it shows the names of the fathers of my great great grandmother and father. Not surprsingly, their respective lands were very close.
If you write me at citellus2 at aol dot com, I may have some other sources of surname information for that time period. I am away at present and do not have that information with me.