So, the marriage record looks like it says, "Ondrup" and sure enough, there's a town called that near Selm (and Olfen). Checking those records starting in 1765 for Johan Bernard Schemmer...

03 Oct 1766 - Joes. Bernard, son of Johan. arens Schlarmer - I don't know... link

Didn't find anything else, but started going backwards from 1765 and found...

05 Jul 1764 - Johan berend. son of Henr. anens Schlanmar - link (on the same page is Anna Cath. d/Johannes erend Schlarman?




Johan Bernard Schemmer
Germany Marriages, 1558-1929

Name: Johan Bernard Schemmer
Event Type: Marriage
Event Date: 21 Apr 1812
Event Place: Selm, Lüdinghausen, Westfalen, Preußen, Deutschland
Event Place (Original): Sankt Ludger, Selm, Westfalen, Prussia
Gender: Male
Age: 46
Birth Year (Estimated): 1766
Spouse's Name: Anna Catharina Holterrah
Spouse's Gender: Female
Spouse's Age: 34
Spouse's Birth Year (Estimated): 1778