I have information on 32 Dennewitz names, beginning with Johnathan Gottleib Dennewitz - b. 1743 / d. 1832.Here is what I have on Mary Magdalene Snyder: b. 05 July 1854 / d. 29 April 1899 Ross County, Ohio Burial: Baptist Hill Cemetery, Huntington Township, Ross County, Ohio.
I don't know if you're still looking for this information, but I would appreciate any information concerning the Dennewitz family, spouses and children that any of you may have.
Mary Snyder had a son, Jacob Stephen Dennewitz, who married Mary J. Burkett, who had daughter Mary Ellen Dennewitz, who gave birth to my grandmother, Helen Addie Belle Stafford.