sink holes in michigan

Scientists studying submerged sinkholes in the Great Lakes off the coast of northern Michigan have stumbled onto something they never expected to find: life forms akin to those found in some of ... Natural limestone sink holes in the area create an interesting topography which can be explored along hiking/biking trails through the campground and surrounding area. Rustic campground includes vault toilets and potable water from well hand pump. Recreation Passport required for entry. Though there are more than 200 sinkholes in Michigan's northern lower peninsula, most are located on private property. Only the sinks that make up Thunder Bay