All of the features that we will see, describe, discuss and interpret were created during the last North American glacial age called the Wisconsinan Glacial episode. It lasted from about 75,000 to 10,000 years ago.
Eskers are evidence of subglacial streams.
They are composed of layers of sand and gravel deposited by moving water. They differ from till by being stratified and sorted. Geological History Glaciers are always moving forward. They are simply large sheets of ice sliding downhill. As they move they shape the land over which they are passing by either eroding the land or depositing material.