884. J. A. Allen—Fossil Passerine Bird from Colorado. 
the lower slab. The bones adhere about equally to the two 
faces. The drawing is made from the lower slab, with some 
of the details filled in from the upper one. The feather im- 
pressions are about equally distinct on both, and where in 
either case the bones are absent, exact molds of them remain, 
so that the structure can be seen and measurements taken almost 
equally well from either slab, except that nothing anterior to 
the breast is shown on the upper slab. 
The species here described is of special interest as being the 
first fossil Passerine bird discovered in North America, 
Professor O. C. Marsh in 1872, from the Lower Tertiary of 
Wyoming Territory. Probably the insect-bearing shales of 
Colorado will afford, on further exploration, other types of the 
higher groups of birds. 
For the opportunity of describing these interesting specimens 
I am indebted to Mr. S. H. Scudder, who obtained them during 
Professor O. C. Marsh in 1870,* who refers to it as “the distal 
portion of a large feather, with the shaft and vane in excellent 
preservation.” 
*This Journ., II, vol. xi, p. 272, 1870. 
