Massachusetts
Provincetown, Massachusetts, is located at the tip of Cape Cod, which is constantly being swept west and south by wave action, forming the hook shape.
Primitive shacks can be found throughout the shifting sand dunes of Cape Cod National Seashore. Many of these historic structures were originally used as warming stations for Coast Guard members on patrol.
Jutting out into the Atlantic Ocean like a boxer’s arm flexed for a blow, Cape Cod is among the most distinctive landforms on the East Coast. This sandy peninsula, a famous summer beach retreat, was built by ice. During the last ice age, the Laurentide Ice Sheet advanced and retreated across New England numerous times, leaving a legacy of huge boulders, shallow ponds, rocky moraines—and Cape Cod.
Around 23,000 years ago, the Laurentide Ice Sheet reached its maximum southward extent, dipping down from Canada across the eastern United States in a frozen arc that stretched from New York City to Chicago. As the climate began warming, the ice sheet retreated north and by 18,000 years ago, the landform that would become Cape Cod was revealed. At the time, sea levels were much lower than they are today and the peninsula was much larger, without its distinctive shape. Over time, rising sea levels and erosion have produced the familiar upraised fist we see today.
Clues to the cape’s glacial past can be found all over the peninsula. The entire landform follows the outline of a terminal moraine, a collection of rocks and debris carried to the end of a glacier and deposited as the glacier melts and retreats. House-sized boulders called glacial erratics can be found throughout the cape, carried by moving ice and dropped in place when the ice melted.
The peninsula is also riddled with shallow pools or kettle ponds, created when chunks of ice left behind by the retreating glacier were buried by sediments, which insulated the blocks and kept them intact for hundreds or thousands of years. After the chunks of ice finally melted, the sediments slumped into the holes, which filled with water to become kettle ponds. Wild cranberries and many of the cranberry farms found on Cape Cod and throughout Massachusetts thrive in these kettle ponds, also known as bogs.
Cape Cod is famous for its summer crowds, which descend upon Provincetown (at the tip of the peninsula) by the millions. But while developed parts of the cape are densely packed on summer weekends, quiet spots can still be found in the rolling sand dunes of Cape Cod National Seashore. Visitors should enjoy this area while they can. Geologists estimate that the peninsula will disappear altogether in a few thousand years, as sea levels continue to rise.
On flights to Boston, Massachusetts, or New York City, look for a long spit of land shaped like a bent arm with a flexed fist.
