Passage - Canyon

: Because of their vertical nature, they often require "chimneying" (bracing against opposite walls) to traverse.

: They can vary from narrow "keyhole" slots to massive galleries over 100 feet high. Canyon Passage

: The film was praised for its location shooting in Oregon, which provided a more realistic and verdant backdrop than the dry desert landscapes typical of Westerns at the time. 2. Speleology: Canyon Passages : Because of their vertical nature, they often

: These are typically formed by underground streams that erode downward through bedrock (often limestone). This process creates passages that are taller than they are wide , resembling narrow surface canyons with a cave ceiling. Characteristics : Characteristics : : Technical reports from the National

: Technical reports from the National Speleological Society detail accidents occurring within these specific cave structures. How Mammoth Cave Formed - National Park Service