UPPER TRIAS OF EASTERN ALPS. 659 



such quadrupeds may have succeeded to another, until at a later era, 

 and after the interval marked by the Wealden and Cretaceous rocks, 

 another and a different geographical state of things being established, 

 the tertiary mammalia of Europe entered on the stage and occupied the 

 same area. 



The advocates, however, of the doctrine of progressive development 

 will offer a different explanation of the phenomena* They will refer the 

 large admixture of marsupials in the Stonesfield and Purbeck fauna to 

 chronological rather than to climatal conditions, — to the age of the 

 planet rather than to the state of a portion of its dry land. In the 

 Triassic and Oolitic periods they will say the time had not yet come 

 for the creation or development of more highly organized beings. Ex- 

 perience must test and determine the soundness of these theoretical 

 views. In the mean while it may be useful to bear in mind that while 

 Australia supports at present 100 species of marsupials, the rest of the 

 continents and islands of the globe are tenanted by about 1,700 species 

 of mammalia, of which only 46 are marsupials (namely, the opossums 

 of North and South America), and in like manner there flourished in 

 the Pliocene period throughout Europe, Asia, and America, so far as we 

 yet know, a placental fauna, consisting of species now for the most part 

 extinct, which was coeval with the extinct Pliocene marsupials of Aus- 

 tralia. Such facts, although far to limited to enable us to generalize 

 with confidence, seem rather to imply that at certain periods of the 

 past, as in our own days, the predominance of certain families of terres- 

 trial mammalia has had more to do with conditions of space than of 

 time ; or in other words, has been more governed by geographical cir- 

 cumstances than by a law of successive development of higher and 

 higher grades of organization, in proportion as the planet grew older. 



DISCOVERT OF MAMMALIAN REMAINS IN ROCKS OF HIGH ANTIQUITY 

 IN NORTH CAROLINA, UNITED STATES. 



Although only six weeks have elapsed since the foregoing remarks on 

 the Purbeck mammals appeared in the first edition of this Supplement, 

 a remarkable addition has already been made during this short interval 

 to our knowledge of the ancient geographical range of Secondary 

 Mammalia. Dr. Emmons, in the newly published volume of his "Amer- 

 ican Geology" (Part VI. p. 93), announces that last year (1856) he 

 met with three lower jaws of an insectivorous mammal in the Chatham 

 Coal-field in North Carolina. He has given a figure of the outside of 

 the ramus of one of these jaws, nine-tenths of an inch in length, con- 

 taining ten molars in a continuous series, one canine, and three incisors. 

 The three posterior molars are tricuspid, as in Spalacotherium ; the 

 four next, multicuspid ; and the three anterior ones are simple, conical, 



