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 



Richmond Infusorial Earth. — a, Pinnularia peregrina; b, c, Fragilaria pinnata; d, Gram- 

 matophora oceanica; e, Spongiolithis appendiculata ; /. Gallionella sulcata; g, transverse 

 view, id.; //, Actinocyclus bioctonarius; ?', Cose i nod iscus apiculatus; j, Triceratiuni obtu- 

 sum; I; Actinoptychus biternarius: /, Dictyocba Crux; m, Dict^'ocha; n, fragment of a 

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



of Richmond, besides a few Poly cystines (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 



