No.i.] COPE ON HORIZONS OF EXTINCT VERTEBRATA. 49 



It appears, then, that the term Pliocene or Subapennine is applicable 

 to the horizon of this fauna in Europe and ISTorth and South America. 



RESUME OF COMPARISONS. 



The conclusions to be derived from the facts enumerated in the pre- 

 ceding pages are as follows : 



I. Portions of all the faunse of all the i^rimary divisions of geologic time 

 have been recognized on both the European and Korth American con- 

 tinents. 



II. Parallels requiring general identification of principal divisions of 

 these faunae may be detected. These are: the Ooal-Measures 5 the Per- 

 mian ; the Laramie ; the Maestrichtian 5 the Eocene ; the Miocene. 



III. Exact identifications of restricted divisions may be made in a few- 

 instances only; such are the Turonian and the Niobrara ; the Suessonian 

 and the Wasatch ; the Eqiius deds and the Pliocene. 



It is not impossible that some of the relations mentioned in II will be 

 by the accession of further information, referrible to the list of exact 

 comparisons in III. In all cases of identification it will be necessary to 

 employ the name first i)roposed with definition, for the horizon, other 

 names taking places as synonymes. But in the majority of strata it will 

 be necessary to preserve the local names: thus those of Judith Eiver, 

 Bridger, White Eiver, and Loup Fork, applying to beds having no exact 

 equivalents in Europe, cannot be set aside for older ones, but must 

 themselves be apphed to corresponding faunal horizons elsewhere, should 

 any such be found in future. And it will rarely happen that the minor 

 subdivisions of such faunse will be found to have an extent sufficient to 

 warrant their ha^'ing other than local names. 



In the accompanying diagram the series of strata of Europe and ]N^orth 

 America, as determined by their palaeontology, are placed side by side for 

 the purpose of comparison. Complete parallelism can only be predicated 

 of divisions of the first order separated by horizontal lines. Such rela 

 tion is indicated by exact opposition of the areas representing the epochs 

 in question. In giving the minor divisions of the European epochs I have 

 generally restricted myself to those of the epochs which have American, 

 equivalents. Where there is no equivalent on one side or the other, the 

 vacancy is represented by a diagonal line. In employing names for 

 epochs and their divisions, I have adhered to the law of priority as far as 

 my knowledge of the literature allows.* I have given a few names tf* 

 American formations, but only in instances where such had not been 

 previously given. In such cases I have preferred employing the name of 

 some characteristic genus of fossils, rather than one of local origin. 



* lu the European system I have been much aided hy the atlas of Prof. Renevier of Lau- 

 sanne, and by the writings of Woodward, Gervais, Hubert, Pomel, Gaudry, Filhol, etc. 



Bull. V, 1 4 



