1912] Miller: Pacific Coast Avian Palaeontology 69 



sected by river canons. The indications are that the actual 

 elevation at present is considerably greater than that during the 

 deposition of the bone-bearing material. Certainly the relation 

 of the cave to the river level has changed in the neighborhood of 

 eight hundred feet. There is no evidence of a later subsidence 

 noted, so we may assume that the conditions during the period 

 of deposition were more like those at Rancho La Brea than they 

 are at present, i.e., less abrupt elevation and a smoother top- 

 ography. The presence of Dendragapus in the cave deposits is 

 an indication, however, that conditions were not identical in 

 the two localities. 



A very interesting description of the various chambers and 

 galleries of the cavern is given in Sinclair's paper. The fossil- 

 bearing matrix represents the accumulation on the floors of the 

 chambers and pockets in the form of fans of detritus, admitted 

 doubtless through old chimney-like chutes now entirely blocked 

 by limestone accretions and washed debris. These fans of ac- 

 cumulated material were encrusted, and in some instances 

 cemented, by stalagmitic deposits so that blasting had to be re- 

 sorted to in places. 



The remains are in most cases entirely dissociated. Sinclair 

 notes the finding of a few skeletons in their proper anatomical 

 relations, such as those of a squirrel, a woodrat, a snake, and a 

 bat. These are all animals which would go into caves of their 

 own accord and after death fall upon the floors of the caverns. 

 No case of bird skeletons in any degree associated is to be found. 

 The bones have entirely lost their organic matter and appear 

 almost as though calcined. Perfect bones of the smaller verte- 

 brates are rare. In most cases fracture has occurred and in 

 many the articular surfaces have been injured, either on account 

 of the delicacy of the cancellated bone in that region, or because 

 the presence of articular cartilages tempted the appetites of 

 gnawing forms. Weathering and cracking due to exposure on 

 the surface is the only reasonable explanation of the imperfec- 

 tions of some specimens. 



Sinclair suggests three methods of possible introduction of 

 animal remains into the cave. Washing by rills which carried 

 bones from the surface down by way of the nearly vertical chim- 



