144 



Report of the State Geologist. 



These figures also show marked increase in the vertical diameter of 

 the final volution accompanied by increased lateral compression, x 5. 

 All the specimens figured above are from the calcareous concretions 

 of the Naples beds in the vicinity of Honeoye lake, N. Y. 



Figure 10. A mature shell of the proportions attained by specimens of 

 ordinal')- occurrence. This is an internal cast of about 4 volutions 

 and is approximately complete in length. The form of the suture is 

 ephebic throughout the final 1 volutions. The outer whorl is 

 laterally compressed and subsagittate in section (see front view of 

 this specimen, plate IV, fig. 16). Natural size. From a concretion in 

 the soft shales at Naples, N. Y. 



Figure 11. Transverse section of a mature shell, a part of whose interseptal 

 cavities are filled with deposits of black and white crystalline calcite 

 and the others with calcareous matrix of red and green tints. There 

 is some difference apparent in the septal intervals. 



Figure 12. A similar section of a smaller shell showing the length of the 

 habitation chamber. 



The last two specimens are from the goniatite concretionary layer in 

 Parrish gully, Naples. 



Manticoceras tardum, sp. nov. 



(See Plate VI.) 



Figure 13. A complete, unbroken young shell, showing the continuation of 

 equal varices throughout the entire neanic stage. Although growth 

 has progressed to nearly three volutions, the ornament is ananeanic 

 compared witli Mantic. Patter$o?ii. x 10. Honeoye lake, N. Y. 



Manticoceras simulator, Hall (sp.). 



Figure 14. The original specimen showing the rounded interior lobe whieh 

 is metephebic in M. Pattersoni. Natural size. Near Ithaca, N. ^ . 



