This split , however , failed : the continent reclosed , leaving only a few igneous intrusions , and some oil fields , as evidence that it happened .
Had this continued , Illinois might have resembled the Arabian Peninsula , a broken terrain between two continents .
This split , however , failed : the continent reclosed , leaving only a few igneous intrusions , and some oil fields , as evidence that Illinois happened .
Had this continued , Illinois might have resembled the Arabian Peninsula , a broken terrain between two continents .