ASPHALT GROUP OF FOSSIL SKELETONS 295 



have completely disappeared, dissolved out by the petroleum and long since 

 converted into bitumen, water and gases. The skeletons are never articu- 

 lated; the bones are all jumbled up together in a crowded mass by the slow 

 internal movements of the half-liquid asphalt in which they were entombed 

 thousands of years ago. 



It is safe to say that the La Brea asphalt is the richest repository of fossils 

 ever discovered, if we consider the variety of extinct animals found in it, 

 the perfect preservation of their remains and the ease with which they can 

 be extracted and cleaned up. It is practically unique: asphalt deposits of 

 this type are common enough wherever an asphalt base petroleum comes or 

 has formerly come to the surface, but bones have rarely been found in 

 them and never upon any such scale as this. 



How many kinds of animals are represented in the collection is not yet 

 known. Over fifty species of birds have been identified, and there are 

 probably at least as many kinds of mammals. The most remarkable fact is 

 the great abundance of carnivorous quadrupeds and birds of prey. Wolves, 

 lions and sabre-tooth tigers, eagles and vultures are the most common of all 

 the remains found ; next to them stand the larger herbivora, bisons, horses, 

 ground sloths and larger ruminants and wading birds; while remains of 

 smaller quadrupeds and perching or ground birds are comparatively rare. 

 This is a fact of grim significance, for it indicates that the larger quadrupeds, 

 venturing out upon the seemingly solid surface and caught in the asphalt, 

 served as a bait for animals and birds of prey, luring them from all the 

 country round about and enticing them within the treacherous clutch of the 

 trap. These in their turn, falling victims, served to attract others of their 

 kind. And so the "death-trap of the ages," as a poetically-minded Cali- 

 fornian writer called it, self-baiting, automatically disposing of its prey, 

 has collected and preserved to our time a truly wonderful series of the preda- 

 cious animals and birds. The smaller animals, light and active and seldom 

 venturing beyond the brink of the pool, were not often caught. 



In February of this year (1913) the writer paid a visit to this locality at 

 a time when excavations were in progress for the University of California. 

 The object was to study the conditions at the "tar-pits" as a guide to the 

 construction of a characteristic group exhibit for the American Museum, 

 and to secure by exchange with the Californian museums a full representa- 

 tion of the fossil fauna. Every possible courtesy was received from the 

 several institutions mentioned in getting together the necessary data and 

 materials and especially from Professor J. C. Merriam of the University of 

 California. The group as it stands is based chiefly upon the studies and 

 conclusions of Professor Merriam, so far as we have succeeded in understand- 

 ing and expressing them correctly. In effect, it is meant to convey a picture 

 of the operation of this Pleistocene death-trap. No attempt is made to 

 cover the skeletons with flesh and hide — this the visitor may imagine for 



