Regards you inquiry about Solomon Fountain.Tombstones of Sussex County had a number of Fountains (all d. late 1800's to early 1900's), but no reference to Solomon.Likewise, Scharfs History of Delaware had a few, but not Solomon.Runks Biographical and Genealogical History of Delaware did have one reference to a Solomon Fountain, "(1) Elizabeth Carpenter; m. Solomon Fountain of Delaware City."Based on the substantial accompanying data on the Carpenter family, I'd estimate the marriage to have been about 1850 (+/- 5 yrs).
Delaware City is in New Castle Co, but the Carpenters were all from Cedar Creek Hundred of Sussex County.
If that is a fit, I'd be happy to forward the Carpenter information.(Elder Carpenter was said to be a Revolutionary War soldier which would make you eligible for DAR).