THE 



GEOLOaiCAL MAGA.ZINE. 



NEW SERIES. DECADE II. VOL. III. 



No. II.— FEBRUARY, 1876. 



OI^IC3-in^-^3L .A-ZE^TIOXiIES. 



I. — On the Odontornithes, ok Birds with Teeth.^ 



By Professor 0. C. Marsh, M.A., F.G.S., 



Of Yale College, Newhaven, Ct. U.S.A. 



(PLATE II.) 



REMAINS of birds are among the rarest of fossils, and few have 

 been described save from the more recent formations. With 

 the exception of Archceopteryx from the Jurassic, and a single species 

 from the Cretaceous, no birds are known in the old world below the 

 Tertiary.^ In this countr3'-, numerous remains of birds have been 

 found in the Cretaceous, but there is no satisfactory evidence of 

 their existence in any older formation, the three-toed footprints of 

 the Triassic being probably all made by Dinosaurian reptiles. 



The Museum of Yale College contains a large series of remains of 

 birds from the Cretaceous deposits of the Atlantic coast and the 

 Eocky Mountain region, thirteen species of which have already been 

 described by the writer. The most important of these remains, so 

 far as now known, are the Odontornithes, or birds with teeth, and 

 it is the object of the present communication to give some of the 

 more marked characters of this group, reserving the full description 

 for a memoir now in course of preparation. 



The first species of birds in which teeth were detected was Ichthy- 

 ornis dispar, Marsh, described in 1872.^ Fortunately the type spe- 

 cimen of this remarkable species was in excellent preservation, and 

 the more important portions of both the skull and skeleton were 

 secured. These remains indicate an aquatic bird, fully adult, and 

 about as large as a pigeon. 



The skull is of moderate size, and the qjqb were placed well for- 

 ward. The lower jaws are long, rather slender, and the rami were 

 not coossified at the symphysis. In each lower jaw there are twenty- 

 one distinct sockets, and the series extends over the entire upper 

 margin of the dentary bone (Plate II. Figures 1 and 2). The teeth 

 in these sockets are small, compressed and pointed, and all are 

 directed more or less backward. The crowns are covered with nearly 

 smooth enamel. The maxillary teeth a23pear to have been numerous, 

 and essentially the same as those in the mandible. Whether the 



^ From the American Journal of Science and Arts, yoI. x. Nov. 1875. 



^ For some account of previously known Fossil Birds, see an Article on " Birds 

 with Teeth," hy H. Woodward, in the " Popular Science Review," ISTo. 57, October, 

 1875, p._ 337, pi. cxxv. 



3 Silliman's American Joui-nal, vol. iv. p. 344, and vol. v. p. 74. 



DECADE II.— VOL. III. — NO. II. 4 



