By Ann Votaw
As you come to him, the living Stone—rejected by humans but chosen by God and precious to him—1 Peter 2:4
Urban Park Ranger Mara Pendergrass (left) reached through the fence surrounding Holy Trinity Church Inwood. Holding a hard chunk of quartz, she scratched a section of grey rock and noted how the stone’s coating — the patina — changed from dark to white, indicating softness. “This is Inwood marble,” Park Ranger Mara said of the outcropping of bedrock.
Marble is one of three types of bedrock we can see in Upper Manhattan and the Bronx. It is the softer middle layer between Fordham gneiss on the bottom and Manhattan schist on top. What do these sandwich layers of rock look like? The “C” rock across from Spuyten Duyvil Creek is an excellent example of Fordham gneiss, pronounced “nice.” Meanwhile, large formations of Manhattan schist are everywhere in the woods in Inwood Hill Park.
According to Park Ranger Mara, marble is metamorphic, which indicates some kind of change due to temperature, pressure, or chemistry. Marble was once limestone, and limestone was once coral! Yes, millions of years ago, this area was underwater and either farther south or a lot warmer. The rocks we see were once part of a living coral reef that died and calcified to form limestone and finally marble.
So the rocks we see at Holy Trinity are part of a breathing ecosystem that changed so slowly that no human could live long enough to watch their formation. As Christians, we know we are being formed every day, just like the rock on which we stand and pray.