Once the train to New Haven leaves Grand Central Station, which it does approximately every half-hour, it travels underground until it reaches 125th St., Harlem, where it emerges from the depths to travel overground, amongst the buildings either half-constructed or dilapidated, buildings which themselves rest on the rock unit known as the Cambrian and Ordovician Inwood Marble. But it is not until the train moves beyond 125th St., and into the Bronx, that you begin to notice geography, specifically the northeastward-trending structure of the region. The New Haven line traces this natural curve and spoons the coast at it travels through the south-Bronx and into Westchester County. Once it crosses the Harlem River the train balances upon a narrow sliver of the Cambrian Manhattan Formation, until it reaches Fordham and cuts east across a small portion of Cambrian and Ordovician Inwood Marble. The eastward bounding train traverses a bit of the Preterozoic Fordham Gneiss before continuing upon the vast Cambrian-Ordovician Hartland Schist, which makes up the majority of the northeastern seaboard between New York and New Haven.

From the window of the train you can see rock outcroppings jutting from the earth at every imaginable northeaswardly-trending direction. These outcroppings somehow display a combination of necessity - chance - and order that mirrors that strange alchemy of the city one has just departed.

The city, urban life as we know it, is dependent on two things: Rocks and Elevators.