322 Correlation" of the Upper Cretaceous Formations 



the Marshalltown of New Jersey, which like that west of St. Georges is 

 best characterized by the abundance of Exogyra and Gryphma. The 

 Matawan fauna from the Magothy Eiver in northern Anne Arundel 

 County is meager, but is obviously more homogeneous in general char- 

 acter, and the horizons differentiated in New Jersey have not been recog- 

 nized. 



With the relatively unimportant exceptions above cited the Matawan 

 fauna of Delaware and Maryland presents nothing to indicate the pres- 

 ence of the New Jersey faunal subdivisions. Furthermore, the strati- 

 graphic units based on lithologic differences in New Jersey are not 

 present to the south of the Delaware Eiver, so that the New Jersey classi- 

 fication can at best have only a. local application and even there does not 

 represent the most significant faunal values which the terms Matawan 

 and Monmouth imply. 



Among the most characteristic Matawan forms common to Maryland 

 and New Jersey are: Yoldia longifrons, Exogyra ponderosa, Modiolus 

 burlingtonensis, Liopistha alternata, Pholadomya occidentalis, Crassate- 

 lina carolinensis, Corbula bisulcata, Anchura rostrata, Laxispira lumbri- 

 calis, Placenticeras placenta, Mortoniceras delawarensis, Baculites asper. 



The Monmouth fauna is very much larger than the Matawan, much 

 better preserved and much more cosmopolitan in its affinities. There are 

 three areas of distribution in Maryland — one on the Eastern Shore in Cecil 

 County, a second along the Sassafras River in Cecil and Kent counties, 

 and a third in Anne Arundel and Prince George's counties. The Sassa- 

 fras Eiver fauna though prolific is very poorly preserved, and the determin- 

 able species are none of them diagnostic of any particular facies. The 

 most striking difference between the Monmouth of Cecil County, as 

 developed along Bohemia Creek, and that of Prince George's County, is 

 in the cephalopod fauna. The cephalopods are best represented on the 

 Eastern Shore by Belmnitella americana, on the Western Shore by Spheno- 

 discus lobatus. The former suggests the Mount Laurel-Navesink fauna 

 of New Jersey, in which Belemnitella is exceedingly abundant and to which 

 it is restricted. Sphenodiscus, on the other hand, is the most character- 

 istic species of the Tinton and is confined to it. Aside from the presence 



