CEPHALOPODA OP THE OBETACBOUS MARLS. 277 



One tray in the Acad. Nat. Sci. is marked "Vincentown, N. J., T. M. 



Bryan." 



Baculites compressus. 



Plate XL VI, Figs. 1, 2. 



Baculites compressus Say: Am. Jour. Sci., 1st ser., vol. 2, p. 41; Morton, Synop- 

 sis, p. 43, PL IX, Fig. 1, and probably of most authors where western 

 examples are considered. 



Among the specimens sent me from the Acad. Nat. Sci., at Philadel- 

 phia, as New Jersey fossils, I find the type specimen of this species, used 

 by Mr. Say in his original description, and afterward figured by Dr. S. Gr. 

 Morton as above cited. Mr. Say says that the specimen came to him from 

 the collection made by Mr. Nuttal; that it was washed out from the banks 

 of the Missouri River between White River and the Mandan settlements, 

 as stated by Dr. Morton. The specimen was owned by and loaned to Dr. 

 Morton by J. P. Wetherill, Esq., and I find his initials still on it in ink. 

 The specimen has the lithological character of the western specimens, 

 and not that of the New Jersey fossils. The specimen is more compressed 

 than are any of the New Jersey individuals when retaining their true form, 

 and is slightly ovate, being narrower on the siphonal edge than on the 

 opposite. In other respects it presents the common features of the others 

 as to rate of taper, number and position of lobes, and generally so in 

 details of bifurcation of the lobes, except in the divisions of the lobe 

 nearest to the ventral edge, where the divisions are not always bilateral, 

 there usually being a central much branched division, which results from a 

 pressing over to one side of the principal part of the lobe by the greater 

 size of or greater number of smaller branches on the side next to the ven- 

 tral edge. This appears, however, to be more a defect in the specimen 

 than a natural growth, as among a large number of examples of all sizes 

 from the Fort Pierre group on Sage Creek, Dakota, I find this feature 

 entirely absent; consequently it becomes quite impossible to find among 

 western examples features in the detail of structure by which the two 

 species of Mr. Say can be separated. I have given a very accurate figure 

 of this historical specimen, and a detailed enlargement of one of the septa 

 for comparison with the eastern forms. There is, however, one general 

 feature of the western forms in which they differ entirely from any and all 



