EXPLANATION OF PLATE IV. 



Fig. 1. Graptolitiius QUADKiMucnoNATUS?. (Page 65.) 



a. View of one side of <a stipe, cul.arged two diameters. 



b. Same, still more enlarged from gutt.i-percba impression, showing shape of the cells. 

 Fig. 2. GiiAPTOLiriius (Diplograptcs) pristis?. (Page 65.) 



a. N.atural size. 



b. Same, enlarged. 



Fig. 3. GiiATOi.iTiius ramulus. (Page 62.) 

 a. Natural size. 

 6. Part of same, enlarged. 



c. Another part of the same, enlarged from gutta-percha cast, the specimen being a natural 



mold in thale. 

 Fig. 4. Giiaptolitiics (Diplograptus) iiypniformis. (Pago 63.) 



a. Natural size. 



b. Same, enlarged. 



Fig. 5. Monticulipora Dalii. (Pago 66.) 



a. Side view of stem, showing its broken end. 

 Fig. 6. Favistella STEiXATA. (Page 67.) 



a. Top view, natural size. 



b. Side view of cells, showing longitudinal striatiou of the walls. 



c. Single cell, enlarged, showing rays. 

 Fig. 7. Leptjena sericea ?. (Page 70.) 



a. Interior view of dorsal valve. 

 Fig. 8. Stropiiomena fiixitexta. (Page 69.) 



a. Interior view of ventral valve. 

 Fig. 9. Ortiiis biforata var. lykx. (Page 74.) 



a. Ventral valve. 



b. Another ventr.al valve, having hinge-line shorter, and mesial sinus deeper at front than 



nsual. 

 Fig. 10. OiiTins plicatella ?. (Page 72.) 



a. Exterior of ventral valve. 



b. Interior of dorsal valve. 



c. Interior of another dorsal valve, enlarged. 



(f. Fragment, enlarged, showing concentric striiB. 

 Fig. 11. Oirniis occiDENTALis. (Page 70.) 



a. Ventral valve, exterior view. 



b. Dorsal valve, exterior view. 



Fig. 12, KiiYNCHONELLA argentlrbica. (Page 75.) 



a. Dorsal view. 



b. Ventral view. 



c. Side view. 



d. Front view. 



c. Fragment, enlarged, showing concentric, raieed lines. 

 Fig. 13. Kaphistoma TROcniscus. (P.age 77.) 



a. Top view. 



b. Umbilical view. 



c. Side view. 



