Need information on SELZ, Elsass, Germany

My great-grandfather Louis SCHELLHORN (assorted spellings Schelhorn, Shellhorn, Shelhorn) married Emma DIETENHOEFER (assorted spellings Dittenhoefer, Dietenhoffer, Diltenheffer)in New York City, New York, USA in 1871. On the marriage record it says that he was born is SELZ, Elsass, Germ.
I believe that this was a town in Alsace-Lorraine.
Does anyone have information on this town, or know how I can write for any records? Please help me to "cross the Atlantic" and find more records about this family.
Thanks in advance for any help.
Sharon Schwarz