In Europe and elsewhere there's a Carboniferous epoch. We in the U.S. divide the Carboniferous into the Mississippian and the Pennsylvanian. Like those of the previous periods, the Pennsylvanian rocks have been eroded away in Minnesota. However, elsewhere the landscape was dominated by swamp, tree ferns, and horsetails. Compaction turned the vegetation into bituminous cole. During this time the Canadian shield was uplifting. The entire continent was tilting westward.