Ancient History, Part 1

What is now Windsor Terrace came into existence some 12,000 years ago. By the end of the last ice age—the Pleistocene era—the area of modern-day New York City was buried beneath a 1,000-foot-thick iceberg called the Wisconsin ice sheet. During its formation, the weight of this ice sheet crushed the rock beneath it, churning up and pushing forward rocks and boulders. As it melted away, the iceberg retreated, leaving behind sediments like gravel, sand, silt, mud and clay as it gouged valleys into the earth. At the same time, torrents of melting ice and dislodged rocks poured down its sides, forming not just the slopes but even the clay-like soil of our neighborhood.

Where it stopped advancing, a high ridge of debris formed from the tons of rocks cascading from the melting glacier. This ridge is called a terminal moraine, and this one in particular is known as the Harbor Hill Moraine. It forms the backbone of Long Island, including Brooklyn’s familiar elevations of Highland Park, Eastern Parkway, Park Slope and Windsor Terrace, Sunset Park and Bay Ridge. The highest point in Brooklyn, 220-foot Battle Hill in Green-wood Cemetery, is part of this geologic feature, which continues across the Narrows, where it rises to its highest point (410 feet above sea level) at Todt Hill, Staten Island.

A walk through Green-wood Cemetery, with its many hills and valleys, can offer a glimpse of what the terrain of Windsor Terrace was like before it was graded for farming and development. Meanwhile, Olmsted and Vaux exploited geologic features in Prospect Park to enhance their design. The Ravine, for example, was built in a depression—known as a kettle pool—left by the Wisconsin ice sheet, and the lake is on the outwash plain of the Harbor Hill Moraine.