Found in good condition as described. The benchmark has had some of its periphery covered in the past 10 years, but it's still identifiable. Remarkable, too, that this is also a 1909 survey mark (#1038) apparently repurposed for the USGS 1952 benchmark line - it's the only such double stamping that I've seen. This is the 5th 1909 Brass Tablet that I've recovered: 3 in Brooklyn, 1 in Queens (and likely the only survivor of the 3 installed in Queens County), and 1 in the Bronx. There were 33 of these Tablets set; Papa Bear's estimate that a dozen survive may be a little pessimistic, but they are definitely rare. Also - around the corner, on the north side of the school building is another 1909 mark - #1037, a chiseled square.
1037 Chiseled Square
Today I worked my way on foot across the south Bronx along Bruckner Boulevard from Castle Hill Avenue to Willis Avenue, about 5 miles. It was at times pleasantly residential and at times rather gritty industrial. I found about half my targets, including 3 FTFs and one of the original NY City bench Marks from 1909 (this station), so it was not a bad day.
This mark was recovered through a hole in a netting that hung over a scaffolding on what seemed like an unoccupied old school. Without the hole, there would have been no picture of the mark. Although the mark is simple and unimposing, with a coat of old drab gray paint, it was actually a remarkable disk. Instead of using a standard USC&GS bench mark disk, the surveyors in 1952 used an existing mark on the school from the 1909 survey of New York City, and simply added the stamping "V 340". The original engraving "BD. OF EST. & AP." stands for "Board of Estimate and Apportionment".
That was the first city-wide survey done after the joining of the 5 boroughs in 1898. All the marks (well over 1000) are documented in the volume [i]Precise Leveling in New York City[/i] by Frederick W. Koop, published in 1914 (available in the NY Public Library). This mark is NYBE+A #1038.
This particular type of disk, only used in that survey, is the only type I have ever seen embossed by the city. I would guess fewer than ten survive. For comparison, I have attached a really good specimin of this type of disk from Brooklyn (NYBE+A #381, see [url=http://www.geocaching.com/mark/details.aspx?Pid=KU1296]KU1296[/url] for more information).
[Photos:]KU1002 "V 340", Bronx NY
View of the school from across the street. Scaffolding covers the entire front of the building. But for a hole cut in the netting, I could not have photographed the mark.
KU1002 "V 340" (NYBE+A #1038), Bronx NY
The stamping "V 340" was added in 1952 to the existing 1909 bench mark.
NYBE+A #381, Grand Army Plaza, Brooklyn NY
This photo of a similar disk from Brooklyn, shows an excellent specimin of the same type of disk.