IM.ATK X. 



L^ lilorKCTE.N i'lMA.MU.S. 



I'llgu 34. 



Sc- Plati! S->. 



V'\g. 1. A li'ft \)il\(N showiiif; tin? tbi-iii uiiil siirfacp chiu-ai-tKi-s. The fijrnre should also show nunicrous Ktie 



rays on the posterior ear. 



Fiif. 2. A similar left valve, showing considerable variation in tlie siirf:i hai-arters, and strong- lijra 



mental area with a central cartilage-pit. 



Chi'inutii,' (."-ronp. FrTiiMhi, Delmmre Co., N. Y. 



AVICULOPECTEN STRIATUS. 

 Page -22. 

 Fig. 3. A left valve ; the original of fig. 7, p. 264, Geolog. Rept. Fourth Dist. N. Y. 1843. 

 Fig. 4. An enlara-ement of the same, showing niorir distinctly tiie characters a.s dest^ribed. 

 Chemung group. Painted Post, ffteiihen. Co., N. Y. 



LvKIOI'ECrEN ANO.\tI.EFOKMI8. 



I'a^'e .IS 

 S..e Plates 4 ami 82. 

 Fig. .">. A left valve. This specimen is inoi-e correctly rei)resented on plate 82, tig. 2. 

 Chemung group. CliiniiiiKj mch. X. Y. 



LyRIOI-ECTEN TKtCOSTATUS. 



See Plates* 4 and 7. 

 Fig. li. An imjierfect left valve preserving a portion of the striated ligamental area and the cartilage pit. 



Chemung grouj). Chemwiig Co., N. Y. 

 Fig. 7. A small left valve with the posterior side undeveloped from accident or natural deformity. 



Chemung group. Near Hlmlra, N. Y. 

 Fig. 8. .\ lai-ge left valve, showing the byssal notch on the anterior side and the comparative size of the 

 anterior and posterior ears. The posterior ear in the sj)ecimen, shows several ol>.scnre rays 

 and the ligamental area is strongly striated. 



Chemung group. Near Elmira, N. Y. 

 Fig. 9. A fragment of a large left valve ]5reser\nng a more extended posterior ear than usual. The 



anterior ear is too much extended in the figure and should be represented as in tig. S. 

 Fig. 10. .\ l<-f't vaUe with a ])ortion broken away, showing what appeai-s to be thi' right \alve beneath. 

 The stronger radii should Ite continuous over the interval occupied by the other valve, and 

 the finer lines on that valve shoidd be of the .same chara('ter jus on the left valve. 

 Chemung group. Broome Co., N. Y. 

 Figs. 11, 12. Two small left valves representing the form and ornamentation of the shell at this period of 

 growth. 



Chemung group. Chemung Co., N. Y. 



