ii \Th UXXXUI c ontioued. 



PtEEINOPEOTBH EXFOLIAT1 9 



r.ui 61. 

 a Plate 1. 



6. A. left valve as obtained IV an impression of the matrix, showing the form and surface characters. 



Pig. 7. A targe imperfect left valve with the test almost wholly exfoliated ami presenting a strong contrast 

 with tin- preceding. 



Li stone of Marcellus shale. Gfenesee Co., -V. ). 



Crexipecten Leon. 

 Page B8. 

 See Plate '.'. 

 Fig 8 'l'l»' left valve described showing the binge characters an. I form uf the valve. 

 Chemung group. Leon, Cattc ■.. .V. Y. 



< Irenipecten liratds. 



[•age -; 

 See Plate 9. 

 Pig. 9. A l.-t't valve showing the form and si/.' of the ears given in correction of fig. 34, plate 9. 

 Chemung gronp. Connewango, Cnttaraug > , .V. 1'. 



Crenipecten [hpoliti a. 



Page - 1 



See Plate 9. 

 Pig. 10. A small left valve. 



Chemung group. Olean, N. Y. 



Pterinea flabella. 



Page vi. 

 See Plates 14 and 15. 

 Pig. 11. A large left valve showing but three strong radii. 



Chemung group. Lawrenveville, Tioga Co . J'u. 

 Pig. 12. 'I'll'- interna] mould of a left valve, showing the ligamental area, lateral ami cardinal teeth, pallia! 

 line ami both muscular impressions. 



Hamilton group. Scftoiorii Co., A. )'. 



l'TEHINEA P1KGTJIS. 

 Page 92. 

 See Plate 15. 

 Pig. 13. A left valve showing Hi.- form and proportions; redrawn from the specimen of fig. 2, plate L6. 

 Upper Helderberg group. Near Columbus, Ohio. 



l'TEHINEA GRANDI8. 

 Page 91. 

 Pig. 14. A large left valve imperfect on the anterioi 



Upper Helderberg group. Lexington, --<">tt Co., I ml. 



