1 



I 



PLATE LXXXI— Contlnneil. 



AviCULOPECTEN TENUIS, 



Page 39. 



See Plate 7. 



Fig. 6. The left valve represented on pi. 7, fig. 23, redrawn to show the true form ami ornamentation, 



with the pallial line and muscular impression. 



Chemung group. Near Salamanca, N. Y. 



AviCULOPECTEN INSIGNIS, 



Page 34. 



See Plates 1 and 3. 



Fig. 7. A left valve preserving the form and proportions in greater perfection than shown on the previous 



plates. Hamilton group. Stafford, Genesee Co., N. T. 



AviCULOPECTEN BELLUS. 

 Page 33. 



See Plate 2. 

 Fig. 8. A light valve, X 2. 



AviCULOPECTEN DUPLICATU8. 



Page 17. 

 See Plate 7. 

 Fig. 9. A left valve showing th<! coarse radii on the pallial margin. 



Chemung group. Mansfield, Pa. 

 Fig. 10. An entire right valve. 



Chemung group. Mansfield, Pa. 



AviCULOPECTEN KUGiESTRIATUS. 

 Page 15. 

 See Plate 7. 

 Fig. 11. A right valve preserving the surface characters with considerable perfection. 



Chemung group. Uockiulle, N. Y. 

 Fig. 12. Several of the railii, of the jireceding specimen, enlarged two diameters to show the changes in 

 surface ornamentation from llio beak to the base. 



AviCULOPECTEN PBINCEPS. 

 Pago I. 

 See Plates 1, 5, 6 and 24. 

 A right valve showing the pallial line and muscular impression. 



Hamilton gi-oup. Ludlowville, iV. Y. 

 A specimen \vith a portion of the left valve removed showing the interior of the right valve ami 

 the diffei-ence in .size between the right and left valves. 



Hamilton group. MuttanviUe, Ontario Co., N. Y. 

 A left valve as preserved in limestone. 



Hamilton group. Delaioare, Ohio. 

 A specimen preserved in a soft shale .showing strong regular concentric strijp. 



Hamilton group. Livinff.iton Co., N. Y. 

 An indivi<lual vertically imbedded in the shales showing the effects of compres.sion and ciistortion. 

 Hamilton group. N. Y. 



