Mabch 8, 1907] 



SCIENCE 



393 



of the Middle Fork of the American Eiver. 

 Its elevation above sea level is 1,300 feet and 

 its elevation above the river at this place is 

 about 650 to 700 feet. 



A perpendicular crevice gives access to the 

 first part of the cave. The opening is partly 

 filled with angular limestone fragments and 

 red dirt to within about eight feet of the top. 

 From the entrance the slopes extend down in 

 a southerly direction for approximately forty 

 feet. At this point two irregular, narrow 

 openings give access to a well-like grotto 

 twelve feet deep. From this grotto a small 

 circular hole leads to the main portion of the 

 cave. To reach this a rope is fastened in the 

 grotto and lowered through the circular open- 

 ing to a depth of twenty-two feet. The rope 

 drops vertically, hanging free from the walls 

 of the inner cave, and the lower end is imme- 

 diately over a small subterranean lake. Near 

 the end of the rope is a narrow tunnel about a 

 foot above the water. This extends south for 

 about six or eight feet, where another pool is 

 encountered. Here a raft, consisting of an 

 air mattress, is called into service, and pad- 

 dling across the water for thirty feet a land- 

 ing can be made on a mud-covered bank. 

 From the south edge of the water and running 

 in a southerly direction for approximately 

 fifty feet is a tortuous series of narrow pas- 

 sages leading into grottos of varying dimen- 

 sions; some of them are very large. These 

 grottos and narrow passageways appear to be 

 the extensions of an open fissure that has been 

 widened by water and weathering. At one 

 time the fissure was loosely filled with pieces 

 of limestone and dirt, and the water running 

 through has cemented it with a deposit of 

 lime, forming a breccia which covers most of 

 the irregularities of the fissure walls, and fills 

 in small openings and grottos where the con- 

 ditions are favorable. The distribution of the 

 breccia indicates that the former filling of the 

 present open spaces has sunk or been washed 

 to a lower level now covered by water. 



The cave is evidently at present in an active 

 stage of growth, as there is a perceptible cur- 

 rent in the water. The work of carving its 

 walls and openings by taking the lime in solu- 

 tion and carrying it away is now going on. 



It differs in this respect from the Shasta caves 

 which have been explored, in that the latter 

 have attained their growth and the Quater- 

 nary openings have been sealed many years. 

 The surface conditions above Hawver Cave 

 by sinks and numerous small openings show 

 where the old fissure was. 



Since the recent removal from the cave of 

 the fossil specimens now in the University 

 Museum the water has risen to such a height 

 that it is impossible to enter the grottos con- 

 taining the bones. This rise in the water 

 level has taken place since the last rains and 

 demonstrates that the presence of pools in the 

 cave is due to seepage and rivulets from the 

 high ground above. It also shows how the 

 fissure contents have been loosened by leaching 

 at times of high water and allowed to sink to 

 a lower level. 



Fossil remains are numerous, considering 

 the small space they occupy. The bones are 

 imbedded in the breccia lining the walls and 

 filling the small openings. High up on the 

 roof blocks of stone have lodged and choked 

 the fissure, and tumbled among the stones are 

 limb bones and other skeletal elements of dif- 

 ferent animals, wedged in and cemented by a 

 film of stalagmite. The bones are in a perfect 

 state of preservation. In some specimens in- 

 filtration has taken place. 



The remains have every appearance of being 

 gradually accumulated in the fissure by fall- 

 ing and washing in from the surface, probably 

 in part through the agency of rivulets. As 

 has been noted from investigation in some of 

 our northern caves, the animals probably used 

 hollows or large crevices in the rocks as re- 

 treats and places in which to eat their prey. 

 Numerous bones were accumulated in this 

 manner, and were in an excellent situation to 

 be entombed in the crevices of the limestone. 



But few bones have been removed so far, 

 though enough are knovm to indicate the age 

 of the deposit and give promise of a rich 

 fauna. 



The most conspicuous of the remains are 

 some excellently preserved Megalonyx bones; 

 these consist of vertebrae, limb bones and a 

 tooth. Also the remains of a cougar (Felis 

 hippolestes ?) and of a horse (probably Equus 



