Since the drainage from the Baraboo went to the Wisconsin, the Baraboo lake was not at first lowered below the level of the highest obstruction in the valley of the Wisconsin even after the ice had retreated beyond that stream. As the drift obstructions of the Wisconsin valley were lowered, the levels of all the lakes above were correspondingly brought down. When the level of the waters in these lakes was brought down to the level of the moraine dam above Baraboo, the one Baraboo lake of earlier times became two. The level of the upper of these two lakes was determined by the moraine above Baraboo, that of the lower by the highest obstruction below the moraine in either the Baraboo or Wisconsin valley. The drift obstructions in the Baraboo valley were probably removed about as fast as those in the Wisconsin, and since the obstructions were of drift, and the streams strong, the removal of the dams was probably rapid. Both the upper and lower Baraboo lakes, as well as the Wisconsin, had probably been reduced to small proportions, if not been completely drained, before the glacial period was at an end. _Devil's lake in glacial times._--While the ice edge was stationary in its position of maximum advance, its position on the north side of the main quartzite range was just north of Devil's lake (Plate XXXVII). The high ridge of drift a few rods north of the shore is a well defined moraine, and is here more clearly marked than farther east or west, because it stands between lower lands on either side, instead of being banked against the quartzite ridge. North of the lake it rises about 75 feet above the water. When the ice edge lay in this position on the north side of the range, its front between the East bluff and the Devil's nose lay a half mile or so from the south end of the lake. In this position also there is a well defined moraine. While the ice was at its maximum stand, it rose above these moraine ridges at either end of the lake. Between the ice at these two points there was then a notable basin, comparable to that of the present lake except that the barriers to the north and southeast were higher than now. The melting of the ice supplied abundant water, and the lake rose above its present level. The height which it attained is not known, but it is known to have risen at least 90 feet above its present level. This is indicated by the presence of a few drift bowlders on the West bluff of the lake at this height. They represent the work of a berg or bergs which at some stage floated out into the lake with bowlders attached. Bowlders dropped by bergs might be dropped at any level lower than the highest stand of the lake.