The presence of spruce suggests cool summers, whereas the deciduous trees imply relatively warm winters.Thus, the climate may have been more equable than it is now.What was the climate like when people first came here?Northern Illinois has an unusual climate history due to its latitude and geology. This question has been hotly debated for over a century, especially now with the recent interest in the last Ice Age.According to established theory, sometime during the Pleistocene, around 13,000 years ago, the last great eastern ice sheet, the Laurentian, reached down only to Wisconsin and was already receding.Although the Laurentide ice sheet, which still existed to the north, may have kept the summers cool, it may also have blocked arctic air masses from extending into the Midwest during winter.[So there was a warming trend and a thickening of forestation between 15,000 to 13,000 years ago.According to some, this environment may have driven Mammoth and other large fauna out of their cool grazing lands reducing their numbers into sparsely populated small herds in this region.
A more recent theory propose prehistoric Solutreans of Ice Age France also sailed west to America across the Atlantic Ocean along the south ridge of the polar ice cap more than 18,000 years ago.This cheeky little toddler is even cuter in real life.The head is red and yellow carnelian agate w sparkling clear crystal eyes. This pre-Columbian artifact was probably a child's toy or mother's keepsake; 2 parts.This late-Pleistocene forest of spruce and deciduous trees is unusual in that a forest of similar composition does not occur anywhere today.The implication is that the climate was unlike any climate in North America today.