PLATE A m. 



Fig. 1. 663. 1. Cybele PUNCTATA. (Pag. 297.) 



1 a. An individual nearly entire, showing the proportion of parts. 



1 b, c. The glabella and base of buckler of two individuals of ditFerent size. 



1 d. The cheek separated at the facial suture. 



1 e. Profile of glabella, showing the strong indentations at the base. 



1 /. An enlarged portion, showing the prominent tubercles. 



1 g, h. The caiidal shields (imperfect at the extremities) of two individuals. 



1 i. A small individual. 



1 k. An enlargement of several articulations of the caudal shield. 



1 /. The surface magnified, showing pustules of different size. 



Fig. 2. 665. 3. Aciuaspis {Species undetermined). (Pag. 299.) 



Fig. 3. 666. 3. Phacops trisulcatus. ( Pag. 300.) 



3 a. The individual of the natural size. 



3 6. Enlargement of the buckler, several ribs of the body, and the caudal shield. 



Fig. 4. 667. 5. Ceraurus insignis. ( Pag. 300.) 



Fig. -5. 664. 5. Calymene clintoni. (Pag. 298.) 



5 a. An individual having the cheeks partially separated at the sutures, and crnshed. 



5 6. A profile view of the same. 



5 c. A cheek of a larger individual separated from the buckler. 



5 d. A caudal shield of a large individual in the iron ore. 



Fig. 6. 29S. 2. Calymene blumenbachu, var.? senaria. (Pag. 299.) 



6 a. An individual of large size, much expanded laterally. 



G b. The caudal extremity of the same, of remarkably large dimensions. 



G c. The glabella of the sanae. G d, c. The caudal extremities of two individuals. 



Fig. 7. Fragments of Homalonotus delphinocephalus. (Pag. 299.) 



Fig. 8. Fragments of Phacops limulurus. (Pag- 299.) 



Fig. 9. 669. 1. Bumastis barriensis. (Pag. 299.) 



9 a. The central portion of the cephalic shield, from shaly limestone of the Clinton group. 

 9 6. Front view of the same, showing the elevation. 



9 c. The caudal shield of another individual. 9 d. View showing the convexity of the same. 



9 e. Section of a fragment of limestone, which is mainly composed of the cephalic and caudal shields of this 

 trilobitc. 



9 /. Magnified view of a weathered portion of one of these shields. 



Fig. 10. 668. 1. Beyrichia lata. (Pag. 301.). 



10 a. A fragment of ferruginous slate, covered with the separate valves of this fossil. 

 10 ft. A valve having a subcentral depression. 



10 c. A valve with a subcentral lobe or nucleus. 



10 d, e. The interior of the shell, or impression made by the cast. 



