182 



1874). I mention the present case merely by way of illustration, 

 and not for the purpose of making any special strictures upon my 

 friend Dr. Brewer, who is by no means in this respect an ex- 

 ceptional transgressor. If it is urged that the people would not 

 understand such expressions as the " Alleghanian Fauna," and the 

 like, it may be said that the time has come when they should be 

 familiar with them. Most intelligent people know that isothermal 

 lines vary in direction with the elevation and contour of the land 

 over which they pass, sweeping, in our own country, far to the 

 southward in leaving the lowlands of the Atlantic coast ; that they 

 pass southward of the Appalachian Highlands, and then bend 

 abruptly northward again along their western base. It is time 

 they knew, also, that the different zones of animal life follow the 

 flexures of the isotherms, and that there are natural faunal belts, 

 sufficiently distinct to be capable of recognition, whose bound- 

 aries coincide very nearly with certain of these isotherms. Furth- 

 ermore, that throughout eastern North America, at least, these 

 faunal belts are already well known to specialists of the subject, 

 and that there already exist definite expressions for such cases as 

 the one that has furnished the text for the present note. I will 

 add. also, that so much is already known of the laws of the geo- 

 graphica! distribution of animal life, that one could have safely 

 assumed, from our present knowledge of the general range of 

 the chestnut-sided warbler, that from its being a rather common 

 summer resident in southern New England, it would also be found 

 to breed in the mountainous districts as far south even as northern 

 Georgia. — J. A. Allen. 



GEOLOGY AND PALEONTOLOGY. 

 New Ordek op Eocene Mammals. — At the last meeting of the 

 Connecticut Academy, Feb. 17th, Professor O. C. Marsh made a 

 communication on a new order of Eocene Mammals, for which he' 

 proposed the name Tillodontia. These animals are among the 

 most remarkable yet discovered in American strata, and seem to 

 combine characters of several distinct groups, viz. : Carnivores, 

 Ungulates and Rodents. In Tillotherium Marsh, the type ..f the 

 order, the skull has the same general form as in the bears, but in 

 its structure resembles that of Ungulates. The molar teeth are of 

 the ungulate type, the canines are small, and in each jaw there is 

 a pair of large scalpriform incisors faced with enamel, and grow- 



