80 



University of California Publications. 



[Geology 



SOURCE AND NATURE OF THE MATERIAL. 



During the summer of 1901 an expedition organized and 

 financed by Miss Annie M. Alexander visited the Fossil Lake 

 region for the purpose of collecting vertebrate fossils from the 

 Pleistocene beds. The collections resulting from this expedition 

 were generously donated to the University of California and form 

 part of its collections in vertebrate palaeontology. 



The material assembled consists largely of mammalian re- 

 mains. There are, however some representatives of the fishes, 2 

 and a very interesting collection of bird material. The avian re- 

 mains were first placed by Professor John C. Merriam in the 

 hands of Mr. F. A. Lucas for determination and description. 

 Unfortunately that able student of avian osteology was prevented 

 by the pressure of other duties from giving the collection more 

 than a cursory examination, and after retaining the material for 

 some time he returned it to the University with a purely tentative 

 identification of the various species represented. After the lapse 

 of a number of years, the task is assumed by the present writer, 

 who wishes to acknowledge his indebtedness to Mr. Lucas for the 

 suggestions conveyed by the determinations made by him several 

 years earlier. 



With the exception of several coracoids and two scapulae, all 

 the determinable material consists of limb bones, with a surpris- 

 ing paucity of the dense tarso-metatarsi. Various possible ex- 

 planations for this scarcity of tarsi suggest themselves. The most 

 plausible is here offered. On lakes or other large bodies of water 

 the remains of aquatic birds tend to concentrate along the shore- 

 lines. Owing to the buoyant effect of the air stratum retained 

 within the feather coat, the body may float for a prolonged period 

 or until cast upon shore by the prevailing wind. The naked 

 shank is submerged during this time, as a rule, and is subject to 

 more rapid maceration and to the attacks of water fleas or the 

 aquatic larvae of insects. These influences tend to accelerate dis- 

 articulation by loss of the binding ligaments. The metapodials 

 would therefore be sown broadcast over a wide area ; a result 



2 See Jordan, David S., Fossil Fishes of California. Univ. Calif. Publ. 

 Bull. Dept. Geol., 5. pp. 9.5-144. 1907. 



