PLATE II. 



Fig. 



1. Thamnastraa Browni, Duncan. (Great Oolite). (Page 1 0.) 



2. The calices, magnified. 



3. The costae and epitheca, magnified. 



4. A septum, magnified. 



5. A costa, magnified. 



6. Thamnastraa Waltoni, Ed. & H. (Inferior Oolite.) 



8. > Details, magnified. 

 9.) 



-,,'(■ Isastraa gibbosa, Duncan, and magnified view. (Page 15.) 



\2. Montlivaltia trochoides, Ed. & H. (Inferior Oolite.) 



13. Montlivaltia Morrisi, Duncan. (Inferior Oolite.) (Page 17.) 



