Recently, Dr. John C. Merriam, President of the Carneigie Institute of Washington, Dr. H. C. Bryant, Assistant to the Director of National Parks, E. C. Solinsky, Superintendent of Crater Lake National Park, and the writer were exploring the western portion of the Rim with a view to selecting sites for the erection of observation stations. In a previous year Dr. Merriam had seen a ledge of well glaciated rock in the vicinity of the Devil's Backbone. Dr. Merriam pleased the members of the party very much by leading them to this interesting relic of the Great Ice Age.

The surface of the rock was clearly polished and striated by the great glacier that went down the slopes of the ancient Mount Mazama between what is now Llao Rock and Hilman Peak. This was probably the largest and longest glacier that Mt. Mazama ever had. Its path has been traced far down the Rogue River for many miles.

A deep layer of pumice and other explosive material covered all but a protruding ledge of what is probably an extensive glaciated surface. This shows that Mt. Mazama was not yet dead during the Pleistocene or Great Ice Age.

A fragment was found which could be moved by each of the party taking turns. This was later placed in the temporary museum. Its surface is beautifully polished by the ice sliding over it for many centuries. Running parallel there are several well defined grooves caused by rocks imbedded in the moving ice.