Third Avenue, North from 95th Street, 1876. Telegraph lines along Third Avenue and buildings visible in the distance indicate the late-19th century transition from farmland to the Upper East Side’s familiar street grid. In this photo, Third Avenue is likely being prepared for the construction of the elevated railway tracks. The Third Avenue El’s Upper East Side stations opened in December 1878. Wooden advertising boards for Murtaugh’s Dumb-Waiters and Rising Sun Stove Polish are visible on the East side of Third Avenue, while graffiti on rocks lining the West side promotes “cigars” and “liver oil pills.”

While New York City is certainly best known for its towering skyscrapers and classy historic districts, its earliest monuments of stone are just that: stone. The geologic landscape of the city was formed between 20,000 and 18,000 years ago with the movement of the Wisconsin Ice Sheet down from Canada. The rock and debris deposited from the ice sheet, as well as the valleys it deepened, bedrock it smoothed and glacial grooves it left, formed the landscape of the city that began to grow in the colonial era. In some cases the rocks have been moved or crumbled in the name of urban development. But some of this geologic history can still be seen within the urban environment. This collection highlights some of the more well-known geologic features.