234 Evolution and Distribution of Fishes 



But Leidy (77^:184) and Cope (i/S'^^s) have 

 described species of Amia (Figs. 32,33) and of the some- 

 what related genus Lepidosteus, as well as teleosts like 

 Osteoglossiun, Pimelodiis, Asineops, Erismatopteriis, and 

 Diplomystiis that is allied to Cliipea and as such was des- 

 cribed by some authors. The English Mid-Eocene or Low- 

 er Bagshot series is variable in character and organic con- 

 tents, but, in its lower strata it includes the Alum Bay beds 

 that have yielded about 250 species of plants, largely 

 dicotyledonous; also the Bracklesham beds with marine 

 molluscs, elasmobranchs, and higher marine vertebrates. 

 Similar conditions are shown on the European continent, 

 except that there was a greater persistence of marine de- 

 posits. The most noteworthy of these marine beds are the 

 great nummulitic strata, which form the dominant mass 

 over central-east Europe. 



The upper Eocene or Uinta formation, that may be 

 500-800 feet thick, is a direct continuation upward of the 

 Bridger and Wasatch below, and mainly differs in the new 

 species and genera that have evolved. In Europe the 

 formation again proclaims changing deposits of freshwater 

 and marine beds with their characteristic fossils. 



The flora in all of these indicates a warm temperate 

 to a sub-tropical climate, though there may have been a 

 mixing of temperate region plants, washed down from 

 higher elevations, that commingled with others that grew 

 in warmer and lower ground. Thus species of Pinus, 

 Sequoia, Ginkgo^ Quercus, Nyssa, Magnolia and Liquidam- 

 bar, occur along with palms, Eugenia^ Eucalyptus, Laurus 

 and Ficus. Such a grouping is a sure indication that the 

 prevailing Triassic-Jurassic gymnospermic type of vegeta- 

 tion was being more and more replaced by an angiospermic 

 and mainly dicotyledonous type. 



The invertebrates included a very rich and large series 

 of insects, numerous molluscs, also freshwater and marine 

 crustaceans. The freshwater fishes were now very largely 

 teleostean, but the ancient Jurassic group of the Amiidae 

 is represented by Amia and Pappichthys, the former of 

 which still survives in the North American species A. calva 

 (Figures 32, 33). Similarly the lepidosteans were abund- 



