Where in New York will you find the oldest bedrock?how old is it?

The Inwood section of Manhattan has a Cretaceous outcropping of sandstone at Isham Street and Seaman Avenue. Brooklyn and Queens are basically glacier deposits. In the Bronx Van Cortland Park has some older rocks, although it has mostly been scoured by glaciers. On Staten Island there is an interesting bedrock with a fused xenolith located off Forest Avenue that is by far older. In fact, the xenolith is about 420 million years old.