From the Tertiary Formation. 125 
ements. 
Length of part of lower jaw containing four premolars,. 9°5 lines. 
Depth of jaw below last premolar Bisset 
2 
Width of jaw below last premolar, . 21." 
Antero-posterior diameter of last lower premolar, - - - - - - Mees 
Transverse diameter of same, -------- -- 1-25.“ 
ORL 0 C1OWi 6 iron ca di ke enn eek ani ee ree is 
is species was found by the writer, in the Miocene Shale, 
at Scott’s Bluff, on the North Platte river, Nebraska. 
Fosstn REMAINS OF BIRDS. 
Aquila Dananus, sp. nov. 
An extinct species of Eagle, nearly as large as the modern 
Golden Eagle (Aquila Canadensis Cass.), is indicated by the 
d portion of a left tibia, discovered during our explorations 
in the Pliocene beds of the Loup Fork river. The specimen 
shows, at its lower extremity, the peculiar fore and aft flatten- 
ing, and the oblique, tapering supra-tendinal bridge over a deep 
canal, so characteristic of the recent birds of prey belo to 
this genus. From the tibia of the Golden Lagle, eg raee a 
1 istin- 
hearly related species, the present fossil may » disti 
guished, aside from its inferior size, by the less concave inferior 
and posterior trochlear surfaces, and by the more prominent 
me well defined tubercle at the center of the ento-condyloid 
ace, 
Measurements. : 
Width of condyles in POM coca os swear nero 8° lines. 
Antero-posterior diameter of inner condyle,---------- 525 
Antero-posterior diameter between condyles,-.-- ---- 3°3 f 
Verse extent of outlet of canal below bridge,---- 2° 
* This . 
ee i Shiladelrbes peg Sciences, 1870, p. 11, and American 
: Philadel J 
Naturalist, vol. iv, p. 317. $ Synopsis of Extinct Batrachia, &c., p. 236. 
