Maryland Geological Survey 339 



bohemicus. The second horizon contains a rather meager fauna, but in 

 it is an ammonite identified with Peroniceras loestphalicum, one of the 

 diagnostic guide fossils of the Coniacian. The upper horizon, the only 

 one which is abundantly fossiliferous, contains both Echinoderms, such 

 as Marsupites milleri, and Mollusca, such as Tricholropis konincki, 

 Cytherea plana and Eriphyla lenticularis , which in their European distri- 

 bution are restricted to the Santonian. The more direct evidence for the 

 partial synchroneity of the Matawan with the Trichinopoly is suggested 

 by the presence of an ammonite analogous to, if not identical with, Pla- 

 centiceras placenta. Other identical but more wide-ranging species are 

 Pecten quinquecostata and Grypliaa vesicularis. 



The Arrialoor, as well the underlying Upper Cretaceous formations, 

 lends itself to a triple division. The lower and middle horizons are 

 included within the Campanian and possibly within the Upper Cam- 

 panian. The fauna of the middle Arrialoor is most nearly comparable to 

 the Monmouth and contains Pachydiscus golvillensis, Ostrea ungulata 

 and other forms which characterize the Belemnitella mucronata zone of 

 the continent of Europe. 



Significant similarities to the Monmouth are found in the general 

 aspect of the faunas. Out of the two hundred and sixteen bivalves listed 

 by Stoliczka one hundred and thirty-two, or approximately 60 per cent, 

 are referable to the Prionodesmacea. Affinities in the gastropod fauna 

 are suggested by the Anchuras, the Volutes, Pugnellus and Turritella, 

 especially the Indian form Turritella breantiana and the American T. 

 trilira. Eour of the Chaniacasa occur, suggesting a very slight affinity 

 with the south European faunas. One of the peculiar elements in the 

 Indian gastropod fauna is the large Cerithium fauna, suggesting a 

 shallowing or embayment of the sea sometime during the Arrialoor. 



The upper Arrialoor contains Nautilus danicus, the type fossil of the 

 lower Danian, together with large numbers of foraminifera, particularly 

 Orbitoids. 



Conclusions 



The evidence afforded by the fossil plants as given in the preceding 

 pages furnishes a strong presumption that the Earitan is of Cenomanian 

 age and that the Magothy is of Turonian age. The evidence afforded by 



