The Glacial Epoch
Next came the glacial epoch, when the advancing ice from the northeast came into the Baraboo region; this was a long time after the sea retreated the last time, possibly a period of 100,000 or 200,000 years. Into this gorge where probably once flowed the stream we now know as the Wisconsin River, the ice advanced to the terminal moraine, where the visitor descends just before reaching the lake. At the same time another tongue of cold crept into the valley between the Devil's Nose and the Lake. Had the tongues of ice advanced much farther there would have been no lake. Sand and gravel were washed into the gorge, leaving a deposit hundreds of feet thick. The well at the north end of the Lake is 283 feet deep, the drill stopping before it reached the bed of the ancient stream. In times agone the river must have found its way through a chasm 900 or 1,000 feet deep, a scene as picturesque as that of the present gorge below Niagara Falls.