An ancestor of mine died in 1895 and was buried in the Mt Sinai section of Cypress Hills Cemetery in Queens.
According to the Mount Sinai Archives: "Initially plots to bury indigent patients were donated to the Hospital by Jewish congregations and benevolent societies. In June 1878, land was acquired in Cypress Hills Cemetery for Mount Sinai through the efforts of Samuel M. Schafer, Esq. There were 110 lots, measuring 20 x 20. Most of the 20th century correspondence relates to the management and upkeep of the cemetery plots."
The hospital placed simple gravestones at the head of each plot stating only the grave number and name. It seems that later (some) families, when they could afford one, came back and placed fuller horizontal tombstones on top of the graves.
Most of the hospital's stones are illegible after years of weather beating against the slate engravings and only a few of the fuller tombstones are uncovered enough to be read. Many of them have sunk leaving only a few words or letters visible and presumably there are many more completely covered by dirt and grass.
The cemetery office does not have a plot map with names or records detailing who was interred in which grave. Mount Sinai's archive provided me with a society map, but this too has no names on it.
I have visited the section numerous times trying to spot a name or some words indicating which plot is my ancestors but have been unsuccessful.