238 Evolution and Distribution of Fishes 



by the writer as to Amia, Pappichthys^ Lepidosteus, and 

 other fishes having been common to the lakes of the two 

 areas. 



Accepting such wide general biological relations, certain 

 distributional features of Eocene fishes deserve attention 

 here. Thus according to all present knowledge the great 

 majority of the Cretaceous teleost genera had been oblite- 

 rated by the close of that period. Thus of 75 Cretaceous 

 genera recorded by Woodward {180) only one, namely 

 Dtplomystiis {Histiurus of Costa, Fig 34) passes from Cre- 



FiG. 34. Diplomystus dentatus, a freshwater clupeoid fish from 

 Green River Eocene shales of Fossil, Wyoming. About one-fifth nat. 

 size. (After Veatch). 



taceous to Eocene beds, 29 genera first appeared in the 

 Lower Eocene, 44 genera first appear in the Upper Eocene, 

 and almost wholly in the remarkable Monte Bolca deposits. 

 Now nearly all of the teleosts thus destroyed at the close of 

 the Cretaceous were marine types, derived from freshwater 

 "ganoids" during Jurassic and earlier Cretaceous times. 

 These belonged to the families Elopidae, Albulidae, Sauro- 

 dontidae, Chirocentridae, Ctenothrissidae, Clupeidae, Halo'- 

 sauridae, Notacanthidae, Dercetidae, Enchodontidae, Scope- 

 lidae, Gonorhynchidae, Chirothricidae, Muraenidae, 

 Crossognathidae, Berycidae, Stromateidae, Carangidae, 

 Scombridae, Percidae and Sparidae. Even a few only of 

 the great Cretaceous teleostean families were continued 

 into Eocene and later periods, not, so far as our knowledge 



