Spuyten Duyvil. Loosely translated from Dutch as "Devil's Whirlpool", Spuyten Duyvil is both the name of the creek connecting the Hudson River to the Harlem River and the name of the railroad swing bridge which crosses it. Amtrak's Adirondack service is seen here utilizing the bridge as it makes its way from Manhattan to the Bronx along the West Side line. The steel arch bridge in the foreground is the Henry Hudson bridge which was constructed in 1938 and carries the eponymous Parkway. Aside from the transportation infrastructure, this photo also captures two important bits of geologic infrastructure. The rock outcrop painted with a Columbia University "C" is one of the few places in NYC where the underlying bedrock is exposed and certainly the most prominent. This "basement" strata is referred to as the "Fordham Gneiss" and dates to 1.1 billion years ago and is a rare example where one can see the rock which underlies the actual, younger (450 million year old) rock that supports the tall structures on the island of Manhattan. The second bit of geology can be seen in the background as the cliffs of the Palisades Sill which lines the Hudson River on the New Jersey side. The rock comprising these cliffs was originally formed by a magmatic intrusion which took place at the time the super-continent Pangaea rifted apart (approx. 180 Million years ago), separating North America from Africa and creating the Atlantic Ocean in the process. The name "Palisades" was derived from the fence-like appearance of the diabase rock which was due to the fairly rapid cooling of the magma which, in turn, caused columnar fracturing.
