469 



GENERAJL REMARKS. 



[Cope. 



The preceding list of fifty -six species is doubtless suflaciently character- 

 istic to enable us to form a pretty good idea of the Puerco fauna. 

 Omitting six undetermined species of reptiles, we find the following 

 peculiarities in the remaining forms. As already pointed out the three 

 determined species of reptiles belong to a suborder, which has thus far 

 been only found in the Laramie formation, or Cretaceous No. 6. This 

 gives the Puerco at once a position below all the other tertiaries. The 

 mutilate orders of mammals may be dismissed as being not likely to occur 

 in a lacustrine formation. The orders of land Mammals are represented 

 as follows : 



Monotremata 



Marsupialia 5 



Rodentia 



Chiroptera 



Edentata 



Bunotheria 15 



Tseniodonta 2 



Tillodonta 3 



Insectivora 



Mesodonta 2 



Lemuroidea 



Creodonta 9 



Taxeopoda 25 



Hyracoidea 



Condylarthra : 25 



Proboscidea 



Amblypoda 



Diplarthra 



Garni vora 



Quadrumana 



Total 45 



The above list renders the peculiar facies of this fauna at once apparent. 

 It is the only Tertiary fauna known, from which Perissodactyla are ab- 

 sent. The absence of Amblypoda, one of the oldest types, is unexpected. 

 The lack of Rodentia is remarkable, and perhaps only due to failure of 

 discovery ; but if yet to be found, they must be very rare, and their 

 absence is consistent with their small representation in the Wasatch beds 

 above them. In the large number of Bunotheria, the Puerco agrees with 

 the later Eocenes, but the order is here characterized bjUhe small number 

 of Mesodonta ; and the Lemuroidea are apparently absent. » An especial 

 feature of the fauna is the presence of five undoubted species of Mar- 

 supialia of the family Plagiaulacidae, which has its origin in the Jurassic 



