
THE 
AMERICAN NATURALIST 
VoL. XXV. JULY, 18o1. 295. 


A REVIEW OF THE “DISCOVERY OF THE 
CRETACEOUS MAMMALIA.”? 
BY HENRY FAIRFIELD OSBORN, 
q July, 1889, I received a copy of the “ Discovery of the Creta. 
ceous Mammalia”? from Professor O. C. Marsh, and shortly 
afterwards wrote to the author calling attention to all the points in 
which it appeared to me he was mistaken, and suggested that he 
should revise the paper himself. 
This was a year and a half ago. In the meantime Parts I. and 
II. of the “ Cretaceous Mammalia” have been widely distributed, 
and the discoveries have been accepted without question by many 
who have no special knowledge of the Mesozoic mammals, and 
with considerable hesitation and criticism by those who have; 
I refer especially to the notices by Lydekker, Lemoine,* Cope, 
and Dames? It seems, therefore, that it is important to carefully 
review, in a manner that cannot be misunderstood either by the 
author or by others, what appears to me to be one of the most 
1 Presented to the Society of Morphologists, Boston, Dec. 30th, 1890 ; Academy of 
Natural Sciences, Philadelphia, Jan. 20th, 1891; Biological Society of Washington, 
er 6th, 1891. Printed, with some alterations, in Proc. Phila. Acad. 
\ Discovery of the Cretaceous Mammalia.” O. C. Marsh, American Journal of 
Science and Arts, Parts I. and. II., July and August, 1889 
Manual of beeline’. Vol. II., p. 1268. 
$ Aien of Sciences, Paris, March 3d, 1890. 
Š AMERICAN NATURALIST, June, 1889, p. 490. 
6 Neues Jahrb. f. Geol. Min. u. Pal., mha p. 141-143. 
ee Mo. ‘Bot. Garden, 
Hee ee 
