30 Reports and Proceedings. 



stone and Hythe, and had there examined the Chalk-marl and Upper 

 and Lower Greensands, and he thought that a comparative view of 

 the Norfolk and Kentish beds might be interesting as well as in- 

 structive to the members assembled. 



The Cretaceous group includes the Upper and Lower Chalk, Chalk- 

 marl, Upper Greensand, Gault, and Lower Greensand. 



The late Mr. Woodward, in his " Outline of the Geology of Nor- 

 folk," 1833, divided the Chalk with flints in Norfolk into Upper and 

 Medial, which Mr. Eose considered a legitimate division, justified by 

 characteristic fossils. 



The Upper Chalk has a soft texture, and its characteristic fossils 

 are Belemnitella mucronata and lanceolata, very abundant ; Cardiaster 

 granulosus, Ananchytes ovatus, some peculiar Ammonites, and large, 

 " Paramoudra," or " Pot-stones," as they arc called, so familiar to 

 people in the neighbourhood of Norwich. The Ananchytes is, indeed, 

 common to both the Upper and Medial Chalk, but it nowhere reaches 

 such a size, or is so abundant as in the Upper Chalk, proving that 

 the most favourable circumstances to its development then existed. 

 One or two species only of Inocerami are peculiar to the Upper 

 Chalk. 



The Medial Chalk is harder than the Upper ; Ammonites and 

 Belemnites are very rare in it ; Inocerami exceedingly abundant, there 

 being no fewer than nine species ; the rare Cardiaster excentricus is 

 here met with. Mr. Eose remarked that geologists sometimes stumbled 

 upon colonies of certain fossils, and this Cardiaster is an instance of 

 the kind, which occurred to him in the parish of Swaflfham, not 

 having met with a specimen since ; equally scarce is Cardiaster 

 rostratus, Mr. Eose possessing but two specimens, — locality, Litcham. 



The Lower Chalk is so hard that it is used for building purposes ; 

 Ammonites are tolerably plentiful in it, such as A. peramplvs, A. 

 Austeni, A. Mantelli, etc. ; these, with Belemnitella plena, may be 

 considered characteristic ; as also the following, EcJiinidce, Discoidea 

 cyclindrica and siibucula, Holaster trecensis, found in one locality only. 

 Inoceram-us mytiloides is confined to this stratum. The Chalk-marl 

 is slightly gray in colour, and arenaceous. It may be seen at West 

 Dereham, near the Church, and at Hunstanton cliff"; at the latter 

 place it is well marked by a great abundance of fragments of an 

 Inoceramus. Tiirrilites tuherculatus and Pecten Beaveri are charac- 

 teristic of this bed. 



Of the Upper Greensand, Mr. Eose said, if there be a special bed 

 at the outer oj) of the Cretaceous strata at Hunstanton, judging 

 zoologically, and from position, it is found in the white and red 

 zoophitic beds — those containing the Madrepora paradoxica (Syphonia 

 of Woodward). The Gault in Norfolk occurs as the usual blue clay, 

 and as a red limestone at Hunstanton, viz., the loioer division of the 

 red beds in the cliff. At West Dereham, Pentney, and Gayton, 

 where the blue clay obtains, the small Belemnites with Dentalium 

 ellipticum, and Ammonites dentatus, are characteristic. At Hunstanton, 

 Ammonites dentatus, A. lautus, A. tuherculatus, and others, also Inoce- 

 ramus sulcatus, with the small Belemnites, determine this Lower Eed 



