4 PROCEEDINGS OF THE NATIONAL, MUSEUM vol. 66 



as a result William Palmer and Norman H. Boss, devoted a con- 

 siderable portion of their personal time to the exploration of the 

 Calvert exposures on the western shore of the Chesapeake Bay. Mr. 

 Palmer was fortunate enough to collect a number of very interesting 

 skulls. To Mr. Boss should be given credit not only for the discovery 

 of some very valuable specimens, but also for the diligence and skill 

 he has shown in the preparation of the specimens for study and 

 .exhibition. 



Hecent observations have shown that a number of the genera and 

 species erected by Cope are not distinct types and that those forms 

 which occur in the Calvert Miocene do not necessarily belong to dif- 

 ferent genera from those which are found in some of the Upper 

 Miocene deposits of Europe. While several investigators have ad- 

 duced much evidence to show that most of those cetaceans which in- 

 habit oceans south of the Equator never enter the waters north of it, 

 no one as yet has been able to satisfactorily explain why certain 

 forms that frequent the European side of the Atlantic Ocean might 

 not also be found on the North American coast as well. On this 

 subject much remains as yet to be investigated, but the occurrence 

 of Eurhinodelphis^ Schizodelphis, Squdlodon^ etc., in the Calvert 

 formation indicates that the same genera and possibly the same 

 species frequented both sides of the Atlantic Ocean. It is possible 

 that actual comparison and acquisition of more complete specimens, 

 especially from deposits in northern Germany and Denmark, may 

 supply some much needed information. 



As the distribution of the Cetacea appears to be dependent upon 

 the presence of an adequate food supply and as the organisms which 

 form their food are dependent either directly or indirectly upon 

 temperature, it is evident that those cetaceans which feed upon 

 tropical or subtropical organisms would not be present in waters 

 where temperate or arctic conditions prevailed. Hence in making 

 comparisons between faunas and in attempting to correlate de- 

 posits in which pelagic mammals occur some allowance must be 

 made for possible differences in climatic conditions. According 

 to Dr. W. H. Dall ^° the Chesapeake series should be compared Avith 

 the Miocene of north Germany, Belgium, and Denmark rather than 

 with the more tropical Miocene of southern Europe. The tem- 

 perature of the Chesapeake embayment, however, was considered to 

 have been warmer than at present. The fauna represented is in- 

 dicative of a temperate climate, thus differing from the boreal and 

 subtropical faunas now present on the Atlantic coast. 



"Dall, W. H., Miocene Text, Maryland Geological Survey, Baltimore, pp. cxlix, 

 cl, 1904. 



