Kenneth A. Kershaw, Quantitative and Dynamic Ecology, American Elsevier, 1964

SCHEMATIC ALTERNATIVE DUNE SUCCESSIONS IN THE LAKE MICHIGAN DUNE SYSTEMS

During and after the retreat of the ice-age glaciers from the Great Lakes region the resultant fall in the general level of the lakes left several distinct 'raised baches', with their associated dune systems. These systems, running parallel to the present shore line of Lake Michigan are about 25, 40, and 55-60 ft above the present level of the lake. These old dune systems have all been dated recently by radio-carbon methods and the highest system above the present lake level (Glenwood) turns out to be slightly over 12,000 years of age. The more recently established dunes were aged by morphological studies of the Ammophila colonizing them and growth ring counts of Pinus banksiana which enters the succession at an early stage.