Art. II.— The Melatiosis ©i the Horizons of Extinct 

 Vertetorata of Europe and ]\©rth America. 



By E. D. Cope. 



The history of the succession of life upon any one portion of the earth's 

 surface is replete with matter for speculation. It shows us a series of 

 faunae succeeding each other, each of which, in many instances, com- 

 mences without previous annonncement in the forms of older periods, 

 and disappears without leaving representatives in later ones. With this 

 basis of fact, which naturally enough has been furnished by the longest 

 explored and best known portion of the earth, Europe, we turn to other 

 lands with the ho])e of obtaining further hght upon a subject so Ml of 

 mystery. These types of life, did they originate in a single centre, fi'om 

 which they disseminated themselves? and, if so, did each form originate 

 in a region of its own or not ? Or, did flie same types of generic structure 

 appear at different points on the earth's surface independently ; and, if so, 

 whether cotemporaneously, or at different times? 



For a solution of these and similar questions, we naturally look to a 

 comparison of the facts first established, with those obtained more recently 

 by exploration in other regions. In this quest, no portion of the earth 

 offers greater promise of results than America. As the second great 

 continent, separated from the other by the greatest possible water sur- 

 face, we anticipate the widest diversity in the character of its life-history. 

 If the types of life have originated independently, we will find evidence 

 of it by studying American palaeontology j if their origin has been through 

 gradual modification, America should furnisli us with many interme- 

 diate faunae. 



The identification of the generic types of Korth American Vertehrata 

 has now advanced to a point which renders such a comparison possible- 

 Although the subject is in its infancy, the following pages will show 

 that an important contribution to it can be now made. The compari- 

 sons instituted in this paper commence with tlie coal-measures, and 

 with the BatracMa of that period. As regards the palteozoic fishes, I 

 have not yet devoted that attention to them which is necessary for their 

 discussion, and I refer to the papers of Kewberry for several important 

 identifications of genera as common to the two continents. 



The structure of the BatracMa of the coal-measures is not yet suffi- 

 ciently well known to enable the most exact comparisons to be made, 

 but close parallels, if not identities, of genera exist. Such are the 

 Bull. V, 1 3 33 



