This zone is characterized by more intense erosion with bedrock and boulders exposed. Vegetation is usually restricted to protected areas such as depressions and crevices. Many geological structures are exposed in this zone. Zone 3 Zone 3 is just north of Zone 2 and bordered on is northern edge by a line extending roughly from the angle of BW7 to about 17 post north of the central gate. This zone is a little higher than adjacent zones having given it some protection from tha flooding.
Top soil is present supporting a diversity of prairie plants.
Zone 4 Zone 4 is North of Zone 3, and is another zone of erosion. This current guide only goes north to the drainage channel which extends from the north end of BW7 to the culbert about three post south of the north gate. In this zone the rudists are best displayed along with several other special features.