Don’t you just love these? These grooves are found along the path in the forest of the NYBG, and time and generations of feet have worn them down slightly. They’re glacial striations, gouged out by the rubble on the bottom the ice as it scraped across the hard surface rock.
These can be found in Central Park, too. But not here in the home borough, which is all glacial deposit–made up, come to think of it, with some of that Bronx rock.