PLATE IV. 



Fig. 

 1. 

 2. 

 3. 



4. 

 5.^ 

 6.1 

 7. ' 

 8. 

 9. 

 10._ 



Dimorphoseris oolitica, Duncan. (Inferior Oolite.) (Page 22.) 

 Calicular surface. 

 A calice, magnified. 

 Synopticulas, magnified. 



.Corallum and details of Tliamnastrtea Walcotti, Duncan. (Inferior Oolite.) (P. 19.) 



12.1 



13 

 14.j 



\ Thamnastraa Manseli, Duncan. (Inferior Oolite.) (Page 20.) 



