Dry Room
The Dry Room is named for its relative lack of water. It is the first room in the cave where the River Styx is no longer seen or heard and cave formations are not abundant in this room. However, cave popcorn is present, indicating airflow from the 110 Exit. Visible to the left of the railing are examples of two rock weaknesses that enhance cave development: a fault surface and a bedding plane parting.
Geology
Room Development
There are tilted rock layers on the left side of the Dry Room from the trail. The steeper rock layer is likely a fault surface and the less tilted one is a crack between bedding planes (Roth 20). These rock structures have wide cracks so they are some of the first areas that are dissolved by carbonic acid. Because of this, passages are more likely to develop in these areas. (Palmer 78-80). This fault and crack and other ones redirects water to the edges of the room, making the Dry Room not as wet as other near-surface rooms are during the rainy season (Roth 20).
Cave Formations
Due to the lack of water in the Dry Room, most cave formations are not prevalent. However, there is an abundance of cave popcorn, resulting from slow moving water traveling down the bedding plane. Since it takes so long for water to move through the openings in the bedding, the water is full of calcite when it enters the room. Combined with the strong airflow from the 110 Exit, cave popcorn is formed (Roth 20; Hill and Forti 691).
Hill, Carol and Paolo Forti. “Speleothems: Carbonate.” Encyclopedia of Caves and Karst Science. John Gunn, ed. New York: Fitzroy Dearborn, 2004. 690-692.
Palmer, Arthur. “Cavernous Rocks: Rock Structure: Fractures.” Dayton: Cave Books, 2007. 78-80.
Roth, John. “Interpretive Manual for the Monument’s Showcave”. Cave Junction: Oregon Caves National Monument, 2011. 20-21