Holy ancient seabeds, J. Alfred Prufrock! Remember when I stumbled upon some fossils in a rip-rap bulkhead holding the bay in abeyance? Well, here are some more, at another city location. (This archipelago is much stone-girt.) These rocks are even more littered with the detritus of millions of years ago.
I haven’t been able to find out where these boulders came from. They aren’t local: “The Bronx is gneiss but Manhattan is full of schist,” (not fossiliferous), as the geological wag had it, and Queens and Brooklyn, westernmost Long Island, are glacial deposits. The lighter tan rock above was an anomaly in this rip-rap, perhaps from an entirely different source.
Backyard and Beyond 
Our teacher, Philip Laporta, showed us ancient seabeds in NJ. There are stromatolites and shells there.
Loved this. So much to see if we would only look.
A geologist once told me he didn’t want to go back to the time of the dinosaurs. He wanted to visit the shallow seas of prehistory. The life was diverse and colorful then. But he said he probably would have been eaten pretty quickly.