What layer do visitors walk through primarily in Niagara Cave?

Visitors primarily walk through the Stewartville member in Niagara Cave. The Stewartville member is a specific geological formation that is prominent within the cave system and comprises limestone deposits formed during the Mississippian period. This formation is known for its distinctive features, which contribute to the cave's unique landscape, including various formations such as stalactites, stalagmites, and other speleothems that enhance the visitor experience. By walking through this member, guests are able to appreciate the geological history and the processes that have shaped the cave over millions of years. The significance of the Stewartville member is key to understanding the environment within Niagara Cave, making it an essential part of the tour.