RHODOPHYCE^E, OR FLORIDE^E 



243 



doubt in the Senonian beds (near the top of the Cre- 

 taceous beds) as Lithothamnion, and are thus of the 

 same proved antiquity as the Diatoms. It does not 

 occur massively until the Tertiary rocks are reached, 



Fir,. 84. CoraW-nfi mediterrnnea, vertical section through antheridium 

 highly magnified. (After Thuret and Bornet.) 



when this contemporary genus occurs abundantly in 

 the lower Eocene. The Leitha limestone (Miocene), 

 the Pisolite limestone, and the nummulitic rocks, 

 are largely composed of Litkotkamnion. 



Though of greater abundance in warm tropical 



K 2 



