Ed Note: "On My Shelf" is my review series, covering notable books and events. For more notables, please see the reviews still housed at the old home of Anthropology in Practice.

“New York is not composed of solid substances. It is a dynamic system of multi-layered flows of earth materials that travel through time and space. The marble, limestone, and steel of the City undergo their own continuous process of change, radically remix with everything around them, send out ramifications into deep futures—and couple with what we humans set into motion.

There is no “outside of” the materials and flows that compose our cities. Humans live within and contribute to this mix. These continuous exchanges never add up to zero (as in zero waste or zero carbon footprint). Each interaction between a human and geologic actor in the City adds new directions and new potentialities. When we humans aim for a sum of zero beween our acts of consumption and conservation, we miss the opportunity to acknowledge and respond to the complex geologic flows that propagate beyond zero as we design, build, inhabit, and move through the City.

New York City is a geologic force, shaping us even as we shape it. So proclaims the cover of Geologic City: A Field Guide to the Geoarchitecture of New York. As we construct our urban centers—marvels of modern technologies—we take for granted the ways in which we incorporate the natural history of the spaces we occupy, so that the city-space is at once past, present, and a promise of the future.

Such is the premise of the project by Friends of the Pleistocene meant to highlight the connections we have to our environment through time and space. Geologic City is supposed to function as a field guide to 20 sites in New York City where visitors can experience this connection. For example, Fortitude and Patience, the lions who guard the entrance to the Stephen A Schwartzman building of the New York Public Library, are sculpted from Tennessee marble, which dates to the Ordovician period 460 million years ago. It’s actually a limestone that resembles marble when it’s polished and is the culmination of deposits of bryozoa and other marine life that settled in a shallow sea that once covered Tennessee.

Or consider New York City water, known for being some of the best tasting and cleanest in the nation, which is funneled to us via natural aqueducts shaped in the Catskills via erosion processes. Not all sites are stationary—the paint on New York City taxicabs is derived from crude oil, which we all know has been millions of years in the making. So the cars are not only powered by fuel, but bear a bit of it in their exteriors. And salt, which the Northeast relies on heavily in the winter months to keep the roads clear, has an interesting commodity history that begins with the formation of deposits of this mineral in the Miocene.

Geologic City is a clever and intelligent way to explore and understand the City in terms of its environment. As an accompaniment to the guide, the Friends of the Pleistocene have mounted an exhibit that will run through September 22nd. Visitors get a chance to participate firsthand in the project by viewing these processes in action and sharing their thoughts—examples of many of the forces discussed in the guide are viewable from window stations in the exhibit space.

If you visit, or pick up the guide, drop me a line below and let me know what you thought.

H/T to my awesome friend and colleague Hannah Waters of Culturing Science who suggested this exhibit, and who let me steal borrow her guide.