710 



SCIENCE. 



[N. S. Vol. XVII. No. 435. 



ternary time and to have been deposited in a 

 small body of standing water. The prevail- 

 ing color of the ash is an ocherous yellovf, 

 but some samples have a brownish tint. The 

 deposit varies from a fraction of an inch to 

 a foot and a half in thickness, thinning out 

 toward the northwest and southeast margins. 

 At the former margin it is seen to dip about 

 five degrees toward the southeast. Through- 

 out it is well stratified and shows little mix- 

 ture with foreign material. Chemical analy- 

 sis shows the glass to contain 63.69 per cent, 

 of silica. This indicates that the ash is either 

 andesitic or trachytic, with the probability in 

 favor of the former. Its source has not been 

 determined. It was probably derived from 

 some of the volcanoes of the Cascades, per- 

 haps from Lassen Peak or Shasta. 



Stratum D, beneath the volcanic ash, is a 

 clay layer varying from a small fraction of an 

 inch to three feet in thickness. It commonlj 

 contains angular boulders of limestone and 

 large pieces of stalactite. More or less stal- 

 agmitic cementation is locally present. 



Excavation ceased temporarily at the sur- 

 face of a hard sheet of breccia (stratum E), 

 which lay beneath the last-mentioned clay. 

 This breccia sheet was penetrated at one 

 point, where it was found to be eighteen 

 inches thick. 



During the excavation there was discovered 

 a circular series of chambers not before visible. 

 The opening leading to these chambers was 

 in the west wall of the main cave and was 

 buried beneath about eleven feet of stratified 

 deposits. The northwest gallery of this new 

 series contains a stream of earth derived from 

 that in the main cave. The top of this fan, 

 at the entrance, is level with the top of the 

 hard breccia floor (stratum E). It slopes 

 steeply to the west and has the greater part 

 of its surface covered with white crystalline 

 stalagmite. Near the entrance the stalag- 

 mite contains imbedded bones. Bones were 

 also scattered at irregular intervals down the 

 slope. 



The materials forming the various deposits 

 above the hard breccia floor (stratum E) have 

 been derived largely from external sources. 

 The stratigraphy of the fan excavated shows 



that the greater part of its material entered 

 the cave from the outside through a narrow 

 fissiu-e in the limestone, which can still be 

 seen, choked with earth, forty feet above the 

 apex of the fan. Erom this fissure, earth 

 and bones fell through a chute-like opening 

 to the fioor below. The earth in the westerly 

 lying series of galleries has entered from this 

 same source, sliding to the west as the bottom 

 of the main chamber filled. All the bones in 

 the west galleries are older than those occur- 

 ring above the stratum of volcanic dust in the 

 main room. The volcanic material, in un- 

 disturbed position, lay about two feet above 

 the entrance to these galleries. The fan in 

 the southwest end has also been derived 

 largely from external sources, entering 

 through an opening similar to that already 

 described. In addition to these openings and 

 the existing entrance to the cave, there have 

 probably been others which are more or less 

 completely closed by the formation of calcite 

 growths. 



Although the cave seems to have been 

 formed along a fissure by percolating water 

 removing the limestone in solution, so far as 

 explored, nothing approaching a residual cave 

 earth has been found in place in the lower 

 chambers. There is no evidence to prove that 

 the cave has been excavated by stream action. 

 A few stream-worn pebbles have been found 

 in the lenses of drip-washed limestone frag- 

 ments, but, like the majority of the bones, 

 these pebbles have fallen into the cave from 

 without, and have not been rounded by water 

 action in the cave. 



Bones were found in all the strata explored 

 excepting the volcanic ash. In all cases they 

 have lost their organic matter completely. In 

 the superficial layers of the clay stratum they 

 are commonly blackened, but at deeper levels 

 they are white and quite brittle. In the 

 gravel lenses scattered teeth and small bones 

 of various rodents are particularly abundant. 

 A large percentage of the material collected 

 consists of fractured bones which it is usually 

 impossible to identify. The edges of the 

 fractures are quite sharp, except where they 

 have been gnawed by rodents before entomb- 

 ment. Apart from these fragments, over four 



