Flat plateaus covered with a shallow layer of unconsolidated Farmington loam top soil, produced by glaciers rubbing against sedimentary rock. Most drought susceptible area in Southern Ontario. Some depressions in landscape produce wetter areas. Along north shore, bedrock slopes and forms large cliffs, but south shore is low and rocky with gravel beaches which restrict water flow and create scattered marshes inland along the shore. Forest areas surround these marshes.
Red cedar is seen in the dry grasslands while red-osier dogwood is found on the damp sites.
Located at the limit of distribution of many northern and southern species. Spectacular numbers of migrating passerine birds concentrate at the northeastern tip of this NWA during the spring and fall. The open fields provide an abundant food source for rodents, which in turn provides a food source for birds of prey. Major migration route for owls, especially saw-whet owls. Monarch butterflies and dragonflies also concentrate here in large numbers.