Thank you for your reply. I had visited the web site for the Bureau of Vital Statistics, but had no luck finding the date range of their holdings.
Thank you, as well, for posting the other burials. In fact, I have information from the cemetery on all of them, but the cemetery failed to include their record information on my subject of primary interest, Sarah Ann Ward. When I wrote them about my disappointment, they apologized and sent me an extract of her information, indicating she resided and died in Bridgeport, which confirmed here identity as my great grandmother. My great grandfather is living in Bridgeport in the 1870 census, a machinist in a sewing machine factory. Their youngest child was born in 1867 and he remarried in 1869, so when I stumbled on Sarah Ann Ward in Green-Wood Cemetery with a death in 1868, it seemed to fit. Her maiden name is Martin, which explains why she is the only Ward in the plot. She died on Feb 15 and was buried in Brooklyn on Feb 16. No small feat in those days, but they had to be in a hurry to get typhoid victims into the ground!