University of Oregon archaeologist Luther Cressman's 1938 excavations at Fort Rock Cave placed human habitation in Oregon as early as 13,200 years ago. Cressman's team also recovered numerous examples of sandals woven from sagebrush bark below a layer of Mazama Ash (deposited by the explosion forming Crater Lake about 7600 years ago). Radiocarbon dating of these sandals, now displayed at the University of Oregon Museum of Natural and Cultural History in Eugene and in the town of Fort Rock, has shown some to be over 10,000 years old. This sandal style is known as Fort Rock style, since they were first discovered there. This sandal style is distinct from other variants; they are flat, closed toed and have a twined sole. They have been found at other sites, such as Cougar Mountain and Catlow Caves, as well. Several other prehistoric artifacts have been found at Fort Rock Cave, including basketry and stone tools. The artifacts found by Stephen Bedwell in 1970 were found in one of the remaining unvandalized areas of the cave.
^Brogan, Phil (16 June 1975). "Geographic board okays naming cave after Long". The Bulletin (Bend). p. 2. Retrieved 8 December 2011. "Board directors said the proposal is not a name change - the cavern, oldest known habitation of man in the region, has been known over the years by various names, Menkenmaier Cave, Fort Rock Cave and Cow Cave. It has been known in recent years as Fort Rock Cave, and this has resulted in much confusion with the Fort Rock formation, about a mile and a half to the east. ... Several years ago, Mr. and Mrs. Long formally presented the cave, on Reub Long's land, to the U.S. Park Service. The cave got its Cow Cavern name because Long's cattle sought shelter there from winter storms. ... The Fort Rock basin cave won national attention in 1938 when Dr. L. S. Cressman, University of Oregon anthropologist, found in the old cave a cache of sandals made from sagebrush."
^"Fort Rock: It's too small for a beer license". The Bulletin (Bend). 1 September 1970. p. 7. Retrieved 8 December 2011. "About two miles northwest of the rock is Fort Rock Cave, where the discovery in 1938 of prehistoric sandals established the Fort Rock basin as the oldest known habitat of man in the Oregon country. Anthropologists set the radio-carbon age of the sandals at around 9,000 years. The cave is located on what was once Reub Long's "home" ranch."