fitton's section at atherfield. 295 



several miles from the shore, at depths from thirteen to fourteen 

 fathoms. "The Bench," however, is not quite continuous, but after 

 occasional breaks is found to recur in nearly the same direction, 

 curving towards the west at some distance from the land. 



The fossils of these two lower beds are so very remarkable, both 

 as to character and number, that I have placed them in a group apart ; 

 and it is not improbable that in other places this portion of the 

 section may be of much greater thickness. The clay above is com- 

 paratively much less fossiliferous ; and nothing certainly can be more 

 striking to the eye of a geologist than this sudden influx, as it were, 

 of nearly a hundred new species (for that number at least has been 

 found in the two Perna beds) immediately over, and so connected 

 with the great freshwater deposit beneath. 



The number and size of Gryphcea sinuata in the bed is very re- 

 markable ; some of the specimens are enormously thick, and hollow, 

 almost chambered, by a separation of the plates. 



Fossils of the Lower Perna Bed. — No. 1. 



[The asterisks prefixed to the names in the following lists denote that the species 

 so marked occur for the first time. 



The mark f denotes that the species has not been found in any higher stratum 

 of the series.] 



*Panopaea plicata, Sow. *Perna MuUeti, Leym. 



t* Prevostii, d'Orh. *Gervillia alseformis {Perna, Sow.). 



* mandibula ?, Sow. t*Lima uudata, Leym. 



*Pholadomya Martini, Forbes. semisulcata. 



t* Agassizi, d'Orb. * Cottaldina, d^Orb. {elongata, 



*Tellina ? Sow.) 



*Astarteobovata(^.5eaMmowifM,Leym.). t*Plicatula placunsea. 



*Corbula striatula, Sow. *Ostrea prionota, Goldf. 



*Hemicardium Austeni, Forbes. * carinata. 



*Trigonia caudata, Agass. * retusa. 



*Arca exaltata, Nilsson {A. Gabrielis, *Gryph8ea sinuata, Sow. 



Leym.). * laevigata. Sow. {G. sinuata, var.) 



* RauHni, d'Orb. *Hinnites Leymerii, DesJi. 



*Lucina solidula, Forbes. *Pecten quinquecostatus^, var., Sow. 



* globiformis, Leym. * interstriatus, Leym. 



*Mytilus simplex, Desh. *Terebratula sella. Sow. 



* aequalis, d'Orb. {Modiola, Sow.) * Gibbsiana, Sow. 



* bellus, d' Orb. f* oblonga. 



*Venus parva, Sow. *Rostellaria Robinaldina, d'Orb. 



* fenestrata, Forbes. t*Emarginula Neocomiensis, d'Orb. 



* Ricordiana, <?'0r5. *Natica rotundata ? 



* Cornueliana, «?'0r5. * gaultina. 



*Thetis minor {T. Sowerbii of Forbes's *Serpula ? 



list). *Vermetus polygonalis, Sow. 



* major {T. Sowerbii, var. of f* Ammonites furcatus, Sow. 



Forbes). 



Fossils of the Upper Perna Bed. — No. 2. 

 *Panop8ea Neocomiensis, d'Orb. Panopaea plicata, Sow. 



mandibula, Sow. t*Corbula incerta, d'Orb. 



* elongata. Hemicardium Austeni, Forbes. 



X Pecten quinquecostatus, var. ? The shells from this bed differ somewhat from 

 the P. quinquecostatus of the upper cretaceous system, in being longer, and the 

 lateral areas being nearly smooth, and the intermediate ribs sometimes slightly 

 furrowed. — M. 



