Cayuga Lake and the Ice That Made It
Near Ithaca, New York
The long blue lake stretching north from Ithaca is Cayuga, and it is a scar left by ice. Cayuga is the longest of the Finger Lakes, running about thirty-eight miles north to south, and it is deep enough that its bottom lies below the level of the sea. It did not carve itself.
Over repeated glaciations, the last of which pulled out of this region roughly fourteen thousand years ago, the Laurentide Ice Sheet, a sheet of glacial ice as much as two miles thick, ground its way south across New York. As the ice advanced and later melted, torrents of meltwater trapped beneath it gouged the old river valleys far deeper, leaving a row of narrow, parallel lakes that look, on a map, like the fingers of a hand. That same ice explains the waterfalls.
The main glacier carved the big lake valley deep and fast, but the smaller side streams were left hanging high above it. When the ice retreated, those tributaries had to plunge down into the deepened main valley, and they have been cutting gorges and spilling waterfalls ever since. That is why the south end of Cayuga Lake, right here around Ithaca, holds such an extraordinary density of gorges and falls.
The scenery you came to see is the signature of a vanished glacier, written into the rock.
