512 



CENOZOIC TIME MAMMALIAN AGE. 



II. Life. 



1. Plants. 



1. Protophytes. — About one hundred species of Diatoms have been 

 described by Ehrenberg and Bailey from the Infusorial stratum 



Fisr. 792 B. 



Richmond Infusorial Earth. — a, Pinnularia peregrina ; b, c, Odontidiuni pirmulatum ; i, 

 Grammatopkora marina; e, Spc-ngiolithis appendiculata; /, Melosira sulcata; g, transversa 

 view, id.; h, Actinocyclus Ehrenbergii; i, Coscinodiscus apiculatus ; j, Triceratium obtn- 

 sum ; k, Actinoptychus undulatus ; I, Dictyocha Crux ; m, Dictyocha ; n, fragment of s 

 segment of Actinoptychus senarius; o, Navicula; p, fragment of Coscinodiscus Gigas. 



of Richmond, besides a few Polycystines (siliceous Protozoans) and 

 many sponge-spicules. Fig. 792 B represents a portion of the 

 earth as it appeared in the field of view of Ehrenberg's microscope. 

 2. Angiosperms, Conifers, Palms. — Leaves of plants have been gath- 

 ered from the Lignite beds of Mississippi, the older Eocene of Hil- 

 gard ; from the similar beds of Arkansas, and those of the Upper 



