294 GEOLOGY 



the Sansans and Deep River mammals, and among cetaeeans the presence of 

 Squalodon, Balcena, Priscodelphinus and oilier dolphins. Among the sharks 

 may be cited Carchprodon megalodon, Hemipristis serra and Notidanus primp- 



genius. Oxyrhina, Carcharias, Galeoccrdo and various rays were abundant in 

 the sea bordering the western continent during this period. 



" In Europe corals are rare except at the south; in Maryland Astrohelia 

 and Septastrea represent the group, the waters of Chesapeake time in this 

 region having been too cold for reef corals and too shallow for the deep-sea 

 forms. 



"The Echinoids of the Miocene are as a rule few in species and profuse in 

 individuals; Clypeaster, Scutella, and Spatangus being the most prominent of 

 European, Amphidetus and Scutella of American forms. 



" Among the Vermes Spirorbis is conspicuous, and Balanus among the Crusta- 

 ceans. 



" Among the Foraminifera nummulites are absent, and, in America, Orbi- 

 toides. Amphistegina, Ehrenbergia, Cassidulina, and Ellipsoidina are prominent in 

 Europe, Polystomella, Planorbulina, Rotalia, Textularia, Polymorphina, and 

 Uvigerina in America. Lithothamnion is a common fossil in the marine 

 Miocene of both continents. 



" There are left the Mollusca, which we may examine a little more closely. 



" Cephalopods are rare in the Miocene. The Aturia, which in America does 

 not persist beyond the middle of the Oligocene, in Europe is said to linger a 

 little longer. Nautilus is known from both the east and west coasts of America 

 in the Miocene. 



" In America, among the Toxogiossate gastropods, Terebra (represented 

 by species of the subgenera Hastula and Oxymeris) is notable, there are many 

 Pleurotomoids, the cones are few and coarse, Cancellaria is represented by a 

 notable number of species. The same remarks apply almost equally to the 

 North German Miocene. 



" American Rhachiglossa are numerous. A species of Oliva and one of Sca- 

 phella&t least appear in both America and North Germany. Busycon in the former 

 region is represented by Tuicla'm the latter. Fusus is more abundant in Europe 

 than in America, but the peculiarly characteristic Miocene subgenus of Chryso- 

 domus, Ecphora, is represented in North Germany by a form almost interme- 

 diate between the American E. quadricostata and Chrysodomus decemcostatus. 

 Ancilla, Murex, Purpura, and Tritia are conspicuous in the Miocene faunas of 



Explanation of Fig. 458. — a, Turritella variabilis Conrad; b, Scala sayana Dall; 

 c, Nassa marylandica Martin; d, Terebra unilineata Conrad; e, Solarium trilineatum 

 Conrad; /, Cancellaria alternata Conrad; g, Surcula biscatenaria Conrad; h, 

 Calliostoma philanthropies (Conrad); i, Actceon shilohensis Whitfield; /, Oliva 

 litterata Lamarck; k, Retusa (Cylichnina) conulus (Deshayes); I, Conus diluvianus 

 Green; m, Polynices (Neverita) duplicatus (Say); n, Fissuridea alticosta (Conrad); 

 o, F. griscomi (Conrad); p, Xenophora conchyliophora (Born); q, Crepidula for- 

 nicata (Linne) ; r, Fulgar spiniger (Conrad) \ar.; s, Ecphora quadricostata (Say); 

 t, Siphonalia marylandica, Martin; u, Ilyanassa (?) (Paranassa) porcina (Say). 

 Scaphopod : v, Dentalium attenuatum Say. (After Maryland Geological Survey ) 



