EARLY PENNSYLVANIA FLORA. FROM WEST-CENTRAL ILLINOIS 



39 



TABLE 7— -FREQUENCY OF GENERA IN THE SPENCER FARM FLORA 



GROUP 

 Genus 



Number of 

 specimens 



Percentage 

 of genera 



Number of 

 specimens 

 of group 



Percentage 

 of group 



LYCOPSIDS 



Lepi dodendron 



SPHENOPSIDS 



Mesoca.la.mi tes 



Annularia 



Asterophyllites 



FERNS 



Alloiopteris 

 Dactylotheca 



NOEGGERATHIALES 



Palaeopteridium 



Gulpenia 



Lacoea 



PTERIDOSPERMS 



Alethopteris 



Sphenopteris + Eusphenopter is 

 Megalopteris + Lesleya 

 Rhodeopteridi um 



CORDAITALES 



Cordaites 



17 

 1 



22 



30 



3 



13 



4 



80 



47 



117 



36 



27 



54 



<1% 



4 



<1 



5 



6 

 <1 



3 

 <1 



17 



10 

 26 



40 



33 



97 



227 



54 



<1% 



21 



50 



12 



12 



Total 



454 



100% 



454 



100% 



occurs in a different type of rock (black shale) and contains more lycop- 

 sids, it has several aspects in common with the Spencer Farm Flora 

 {Megalopteris, Palaeopteridium, and Lacoea). However, the typical Namuri- 

 an forms contained in the Spencer Farm Flora have not been found. 



Newberry (1873) described a flora from Youngstown, Ohio, that 

 shows some similarities and Read (19^6) reported a flora from the Dutch 

 Mountain area in Pennsylvania with Lacoea and a species of Palaeopteridium, 



In the Pocahontas Formation of Virginia and West Virginia no com- 

 parable floras have been reported. Megalopteris does occur there, but 

 it is rare. 



