This Is Karst Country

This Is Karst Country. Caves by Land and Sea. The Door Peninsula is a dynamic landscape formed by water and limestone. , The Niagara Escarpment, a high limestone ridge along Green Bay, tilts at a 6-degree angle toward Lake Michigan where it disappears under water. This limestone is easily dissolved by acidic rainwater. The resulting karst topography is defined by sinkholes, disappearing streams, caves, and springs. Since water rushes through Door County's thin soils and fissured bedrock nearly unfiltered, special efforts must be taken to prevent groundwater contamination. , , Dissolution Caves , Door County has some of the state's best examples of dissolution caves Horseshoe Bay Cave near Egg Harbor is the second longest cave in Wisconsin. It formed as slightly acidic water ran through rock fissures and slowly dissolved the stone into chambers. , , Sea Caves , Sea caves form in limestone cliffs when waves work away at faults and weak areas. Some caves are perched high above Green Bay where ancient lakes levels were 30 feet higher than they are in today's Great Lakes. , , [Caption for first photo:] , A flowstone formation in Horseshoe Bay Cave. , , [Caption for second photo:] , Lake Michigan waves are still eroding sea caves at Cave Point County Park. , , [Caption for third photo:] , This sea cave in Peninsula State Park, shown here circa 1920, has attracted generations of tourists. , , [Caption for bottom photo:] , Eagle Bluff in Peninsula State Park features a sea cave formed more than 5,000 years ago when lake levels were much higher.