Interesting. I've got 2 Seth Slawsons, uncle & nephew, and probably neither matches yours. My direct line ancestor is Seth Holcomb Slawson (1850-1926) s/o Jesse D & Rachel Fuller Chase Slawson, who were in NY before they moved west to IL, Whiteside Co. This Seth married Emma Jane Patch in 1871 in Whiteside Co. They moved on to Nebraska and Kansas.

The uncle is Seth Slawson b c1810 "probably" at Palentine, Montgomery Co NY, died in Chicago; married to Matilda XX, about whom I know nothing, in Oneida Co NY. This Seth is s/o David & Addie Kinney Slawson.

My Seth H is his nephew, and we decorate his his wife's graves on Memorial Days, in Jefferson Co KS.