David Somers Risley b. 1759 Atlantic Co. NJ & d. 1806 Tuckerton, Ocean, NJ
Source: Sandy's Family Tree, ancestry.com
However there is a will of a David Risley of Great Egg Harbor, Gloucester, NJ whose wife was Anna.
Also 1800 Census Great Egg Harbor, Gloucester, NJ
David Risley & family
Residence: Atlantic Co. NJ
Monthly Meeting: Great Egg Harbor
Yearly Meeting: Philadelphia
Meeting State & Co.: Atlantic Co. NJ
Source: U. S. Quaker Meeting Records 1681-1935
I didn't find their burial info abt. 1805 in Ancestry nor in FamilySearch.
The Ocean County Historical Society, www.oceancountyhistoricalsociety.org
has the Society of Friends, Little Egg Harbor monthly meeting minutes 1715-1901 and various family history books.
The Gloucester County Historical Society, www.rootsweb.ancestry.com/~njgchs/
might have inventoried cemeteries.
If they died without tombstones, you probably won't find where they're buried. Successful Searching!