RECENT DISCOVERIES IN AVIAN 

 PALAEONTOLOGY. 



FOR reasons long ago pointed out by Lyell, fossil 

 remains of birds are much more rarely found than 

 those of other vertebrates, and, as a rule, occur in a very 

 fragmentary condition. These circumstances, coupled with 

 the difficulty in arriving at accurate determinations, owing 

 to the great general similarity in the skeletal structures in 

 most of the members of the class, have a direct bearing 

 upon the scantiness of the results that have been attained 

 in avian palaeontology. In spite of these drawbacks, how- 

 ever, some not inconsiderable additions to our knowledge 

 of fossil birds have been made during the last two or three 

 years, and a short account of the chief papers on this subject 

 may be of some interest. It will be convenient to take the 

 papers roughly in the order of the geological age of the 

 fossils they treat of, and to commence with those relating to 

 the most ancient types. 



Pre-tertiary Birds. — Unfortunately, with one exception, 

 no remains of pre-tertiary birds have been discovered during 

 the last few years. This is the more to be regretted because, 

 interesting though many of the tertiary birds may be, they 

 are in all essential respects similar to recent forms, and 

 throw no light whatever on the mystery of the origin and 

 early history of the group, the key to which lies buried in 

 the Jurassic and Cretaceous rocks. 



The single exception referred to is an imperfect tibia 

 obtained at Judith River, Montana, from Cretaceous 

 deposits of somewhat later date than those which formerly 

 yielded the remains of Hesperornis and Ichthyornis. This 

 tibia has been described by Marsh (i), who regards it as 

 indicating a bird about two-thirds the size of Hesperornis, 

 to which it is closely related, and has made it the type 

 of a new genus, Coniornis, its specific name being C. alius. 



Tertiary Birds. — In tertiary deposits of various ages 

 and in widely distant localities, some important discoveries 

 of bird remains have been made of late. 



