Mammoths and mastodons were attracted to this area in Illinois shortly after the Ice Age during the thawing of the glaciers to the north.  During The Pleistocene Era which lasted about 1.65 million years, and which ended about 10,000 years ago, ice sheets covered a large portion of North America.  The reason that this segment of Jersey county is so hilly compared to north and east of here is because we are the westernmost extent of the Illinois glacier, that flattened the rest of Illinois as far as Carbondale.   

The thawing of this glacier towards the end of the Pleistocene, and during the summers when it was warmest, created an enormous torrent of water up to eleven miles wide and a hundred feet deep.  This torrent carved the current path of the Mississippi and Illinois Rivers, and carved the bluffs along the Great River Road here and the bluffs along the Missouri River to the south of us. It created verdant banks in a previously barren tundra landscape that attracted the animals such as mammoths and mastodons during the spring and summer.   However, during the winter the river would have dried up when the glaciers to the north refroze, and the area would have reverted to tundra.  Geologists believe that the sediment deposited on the river floor by the river in the summer would have been whipped up by tornado-like winds in the winter, choking everything that lived.  It might have been this dust that choked Benny to death.  We know that the dust must have been horrific because it covered the bluffs in loess up to 50ft deep in areas over this period.  It is possible that the mammoths who wandered into this area walked into what was effectively a trap.