Many thanks for the description from Wallace G. Lane, Jr. (at the FindAGrave.com memorial): "Often visited and photographed, this grave marker is one of the most unique stones in The Green-Wood Cemetery. A bed style marker; the headboard a child's tufted chair, a tasseled coat draped over the side and a small shoe on the seat and the footboard a stool with a sleeping dog. [At some point the headboard & footboard have been reversed.]Source: FindAGrave.com Memorial Number 28696358, Lot 4780 section 22, The Green-Wood Cemetery, 500 5th Avenue, Brooklyn, New York. Photographed 14 May 2015; Wallace G. Lane, Jr.
Unfortunately a large part of the upper left frame of the chair has broken off. The broken piece was not in evidence, but the now exposed stone shows little signs of dirt.
The reverse of the carved chair is just as detailed as the front; button holes and the twist of the tassel cord."
Mary Rosekrans Adsit was a second cousin to my paternal grandmother, Elizabeth Adsit. Their common great-grandparents were Leonard Adsit (1783-1816) and Fanny Davenport (1785-1871). (They're all linked at FindAGrave.)