546 Progress of Ornithology in the United States. [September 
Not only has the geographical distribution of North American 
birds been studied in connection with the general history of each 
species, but attempts have been made to discover and limit the 
different faunal areas of the continent, special attention having 
been given to this department of the subject by Baird, Verrill, 
Allen, and Ridgway, and incidentally to a less extent by others. 
The subject of geographical variation has also been thoroughly 
investigated, with results of high importance, which will later be 
referred to more fully. Among the prominent workers in this 
field are Baird, Allen, Coues, Ridgway, and Henshaw, while the 
subject has received much attention from others. 
Within the last ten years also a field previously wholly un- 
explored has been opened up, that of paleontological ornithol- 
ogy, mainly through the labors of Professors O. C. Marsh and E. , 
D. Cope, the former of whom has alone made known, mostly in 
preliminary papers, the remains of upwards of thirty species, 
found in the Cretaceous green-sands of New Jersey, and the Cre- 
taceous and Tertiary formations of Kansas, Colorado, and Wyo- 
ming. ‘Those described by Professor Cope are likewise mainly 
from the same localities. 
Much has also been written by American ornithologists on 
exotic birds, especially on those of Central and South America. 
In 1838, J. P. Giraud described “sixteen new species ” of Mex- 
ican birds, and Dr. S. Cabot published (1842 to 1844), several 
papers on the birds of Yucatan, describing a number of new Spe 
cies. Mr. George N. Lawrence has published numerous papers 
on the birds of Mexico, the West Indies, and Central and South 
America, and Dr. Bryant on the birds of some of the Lesser 
Antilles. Cassin published not only on the birds of Central and 
South America, but also on those of Africa and other distant 
countries, including reports on the collections made by the United 
States Exploring Expeditions under Commodores Rogers and 
Wilkes. Buaird’s Review of American Birds treats largely of 
the birds of tropical Ameriéa, and some of the monographie a” 
revisionary papers of Coues and Ridgway have taken a wide 
range. D. G. Elliot has published elegantly illustra s 
graphs of the Pittidæ, the Phasianidæ, and the Tarer 
and many papers on different genera of the humming-birds a 
other exotic groups, mostly, however, prepared and publis h 
abroad. Professor Alpheus Hyatt has published a moie 
of the Spheniscidæ, and Drs. Kidder and Coues reports ont 
birds of Kerguelen Island; the present writer reports on ¢ 
ted mono- 
ollee- 
