We are in Wellfleet for the long weekend, and the Lower Cape seems particularly tranquil and beautiful under the blue winter skies. Yesterday the memsahib and I took a little spin up to Provincetown, at the outermost tip of the Cape, and along the way stopped at Longnook Beach in Truro to take a quick peek at that loveliest of littoral landscapes.
Cape Cod is, geologically speaking, a “terminal moraine”. When the vast ice sheets receded at the close of the last Ice Age, they left behind the piles of debris that they had scraped up and pushed before them as they expanded. The Cape and Islands (not to mention much of Brooklyn) were shaped by this process. Here, taken from Arthur N. Strahler’s excellent little book A Geologist’s View of Cape Cod, is a helpful diagram:
As the glaciers liquefied, the meltwater carried silt and fine debris to the east, forming what is known as an “outwash plain”. The shoreline of the early Cape was broad and irregular, as we see below:
Over time, though, the rising sea began to cut back the low sandy shoreline of the outwash plain, and even to eat away at the base of the moraine itself. This resulted in a high marine escarpment along the Outer Cape’s edge:
One result of this erosion of the moraine was that the gullies (usually called “hollows” around here) that formed as the glacial meltwaters found their way to the sea were cut off high above sea level, forming “hanging valleys” at the edge of the marine escarpment. In the Truro highlands, the highest (and narrowest) part of the Cape, is one of the prettiest of these, called Longnook Valley:
At the end of Longnook Road is a small parking lot, where the hollow meets the sea. Getting out of the car one glimpses the blue Atlantic, framed by a notch in the dunes:
Below are two more views, the first looking directly down at the beach 60 feet below; the second looking south.
The Outer Cape is to most people a summer place, but I think it is in many ways at its most beautiful in winter, and perhaps fittingly so: it is the ghost of a departed world of ice.
3 Comments
You have a memsahib, too?!? I thought this was exclusive to Mr. Duff!
Indeed I do. The lovely Nina has been sharing my howdah for 31 years now.
I love Truro and am just back from a day at Longnook. I even own a copy of Strahler’s book, and often (probably too often!) tell folks about the hanging valley description. My question is, given the pitch of the valley, with the high point at the parking tray, wouldn’t the water have flowed east-to-west, away from the ocean? Also, given the decreasing width of the valley, is it possible to conjecture where the east end of the valley was, now out over the sea? Thanks, and your thoughts…?
DH