Llao's Hallway - Prominent Geological Features of Crater Lake National Park
This 125-foot-deep gorge was cut
through pumice material by stream erosion. It is located on Whitehorse
Creek, a tributary of Castle Creek and once contained a trail leading
through narrow passages to numerous cave-like amphitheaters.
Though the pumice flows spread all the way down Castle Creek, the later scoria flows did not extend far beyond the park boundary, a distance of little more than 7 miles from the
source. Moreover, as in other canyons, the scoria flows were confined to a central and narrow depression in the earlier pumice deposits. It is among these scoria deposits that the
only "fossil fumaroles" of Castle Creek are to be found, and they are almost restricted to the part of the canyon above the junction of Castle with Whitehorse Creek. Here the dark
scoria deposits have been carved into the spectacular gorge known as Llao's Hallway, a chasm narrow enough in places to be spanned by outstretched arms, yet 200 feet deep. [The
Climax: Culminating Explosions of Pumice and Scoria: The Castle Creek Flows, The Geology of Crater Lake
National Park, Oregon (1942) by Howell Williams.]
Plate 15. Fig. 2. Llao's Hallway, cut in
massive, unbedded, chaotic deposits of a scoria flow (nuée ardente). (Photo by
National Park Service.) The Geology of Crater Lake National Park, Oregon (1942) by Howell Williams
