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91 of those glaciers can be seen in the glacial till deposits shown in the map below. When the ice reached its maximum southerly extent, parts of the Grand River drainage were cut off and a new drainage (the Ancestral Plains Stream) formed flowing south through Kansas. 39, 159 When the last Kansan ice sheet began to melt, new rivers and watersheds began forming as the ice retreated northward. The ice melt must have started and stopped and restarted numerous times. Whenever it stopped, a new stream drainage formed. If you look at the glacial till area in the map below, you will see a number of streams that line up and follow a north/south path. These must mark where the ice stopped long enough for new drainages to form. 242 For instance, the western edge of the glacial till lines up with Bazile Creek, the North Fork Elkhorn River, Maple Creek, Skull Creek, Oak Creek, Salt Creek and the Big Nemaha River as well as the Big Blue River. If you look closely at a map of eastern Nebraska, you can see a number of streams or portions of streams (such as Logan Creek, Bell Creek and the lower Elkhorn River) that have this same alignment. Is this a coincidence? Perhaps not. Notice in the map above that many of the streams in the state have a generally northwest/southeast alignment. These include the Elkhorn, the Loup basin streams and the Blue Rivers. Then right through the middle is the Platte River flowing northeast, exactly opposite of these other rivers. I noted earlier that the Platte River was one of those large, broad, braided prairie rivers that was constantly moving back and forth across the plains. 2.5 million years ago it was flowing northeast. One million years ago it was flowing southeast. Apparently, it began settling into its present course some 30,000 years ago. 218 It is thought that the rivers in the Loup River basin were originally the headwaters of the Big Blue River basin. 149 At this same time, the lower end of the Platte River was probably the lower Elkhorn River. Then a tributary of the Elkhorn, by working its way west, captured several Glacial till map of Nebraska illustrating how existing stream courses may show the edges of a Pleistocene ice sheet.