SMITHSONIAN EXPLORATIONS, I929 35 



in one of the numerous lava caves of the region. My route was by 

 rail down the Columbia River Valley to Sherman, Oregon, and thence 

 southward up the Dessutes River over a branch of the Oregon Short- 

 line Railway. This railway winds its sinuous way up through the 

 gorgeously carved canyon of the Dessutes River, revealing at every 

 turn new vistas of l)eauty and grandeur, for this canyon and its tribu- 

 taries have been carved deeply by nature's agencies through enor- 

 mously thick and widely extended beds of consolidated lavas, leaving 

 many precipitous canyon walls and here and there rugged isolated 

 buttes of solid lava rock. Arriving at Bend we were welcomed by 

 Mr. W. J. Perry, a government forester who had first reported the 

 fossil bones. The following day all hands with Mr. Perry conducting 

 the party, proceeded to the exploration of the cave. These caves are 

 peculiar and not at all like the ordinary caves of limestone regions. 

 Instead of holes or excavations consisting of irregular chambers and 

 intersecting passages eaten out by the action of acid-bearing waters 

 which have operated to form the great caverns of limestone regions, 

 we find here extended underground tunnels or tubes of relatively 

 uniform size which were formed by melted lava streams continuing 

 to flow for long distances after the main mass of the lava outpourings, 

 which once covered thousands of square miles of that general region, 

 had become partially ccjnsolidated. The present day entrances to 

 these tunnels, when such can he found, are evidently spots where the 

 supports of the tunnel vaults were not perfectly arched and these 

 weaker places have given way to earth tremors or other extra strain. 

 Where these weaker spots were near the surface they have caved in, 

 forming the openings. Tt was through such an opening we entered 

 the " fossil bone cave '" as it has been named by Mr. Perry and is 

 locally known. Equi])ped with miners' lanterns we followed back 

 along the more or less even floor of the cave for several hundred feet, 

 encountering here and there great rugged piles of lava rock broken 

 down from the roof of the old passage left by the lava stream. Over 

 these we were obliged to scramble to reach again the more even floor 

 of the continuing passage way. When we had reached one of these 

 piles of fallen rock about 3.000 feet from the spot where we had 

 entered and where the old lava channel forked to form two passage 

 ways, Mr. Perry announced we were near to the spot where he had 

 first discovered the fossil bones. A little search on our part soon re- 

 vealed more of them and in a few hours we had made a small collec- 

 tion by which we could judge of their nature and form some intelli- 

 gent idea of their history. 



