ART. 26 REMAINS OF FOSSIL PORPOISES KELLOGG 6 



this A'ertebra was discovered in the green sand at Mullica Hill, New • 

 Jersey. Other vertebrae from Shiloh, New Jersey, have been as- 

 signed to this species. 



According to the practice of Cope and others whereby generic and 

 specific names were given to very fragmentary and incomplete re- 

 mains of fossil cetaceans, the opportunities for setting up new genera 

 and species for variations in structural modifications of vertebrae 

 were practically unlimited. Since many of the genera and species 

 erected by Cope and Leidy were based upon parts other than skulls, 

 it has been very difficult to correlate or allocate the material, save in 

 a few instances. The collection which forms the basis for this study 

 comprises a number of porpoises with skulls and associated vertebrae. 

 In studying this material it became evident that a number of well 

 known genera of fossil cetaceans were present in the Chesapeake em- 

 bayment during the Miocene epoch, some of which have not been 

 reported previously. A preliminary study of this material in con- 

 junction with the types of the previously described porpoises in the 

 Academy of Natural Sciences of Philadelphia has convinced the 

 writer that many of the Cope and Leidy types can not be allocated 

 until associated skeletons of all the fossil cetaceans for which skulls 

 are known are found. 



Since Cope was practically the sole investigator of fossil pelagic 

 mammals in North America at the time of his death, it was un- 

 fortiinate that no one came forward to carry on tliis work. Hence 

 interest in the problems involved lapsed. It was not until the Mary- 

 land Geological Survey began preparation of a series of reports to 

 illustrate the natural resources of that State that any further in- 

 terest was shown in the pelagic mammals of the Chesapeake em- 

 bayment. Wlien this series of reports was planned it was found ad- 

 visable to secure the services of a number of specialists, and the 

 pelagic mammals were allotted to Prof. E. C. Case. In the section 

 of the report which deals with the Miocene, Case "^ described a frag- 

 mentary skull and associated mandibles as Priscodelphinus (?) 

 crassangulum. A few years later, True^ concluded that this form 

 belonged in the genus SchizodelpMs. In 1912 ^ True published a de- 

 tailed account of the skull and associated skeleton of Delphinodon 

 dividum. This was the first account of a fairly complete fossil ceta- 

 cean skeleton obtained from the Calvert formation. Following this 

 publication, renewed interest was taken in the Calvert Miocene, and 



' Case, E. C, Miocene Text, Maryland Geol. Surv., Baltimore, pp. 12-13. pi. 11, 1904. 



"True, F. W. Smithson. Misc. Coll. (Quart. Is.), vol. 50, pt. 4, Publ. 1782, pp. 449-460, 

 pis. 69-70, 1908. 



"True, P. W., Journ. Acad. Nat. Sci. Philadelphia, ser. 2, vol. 15, pp. 165-194, pis. 

 17-26, 1912. 



