1869.] WILTSHIKE — ^HUNSTANTON RED CHALK. 189 



the beginning, the pebbles are of larger size, and in which, after- 

 wards, the sandy particles are so loosely held together as to present 

 a strong contrast to the massive nature of the white and red beds 

 above. Covered by the Carstone and adjoining it is a bed of clay 

 marked Z in the section. 



Throughout the space of more than 30 feet below the base of the 

 Red Chalk no fossils have been hitherto found at Hunstanton in the 

 Carstone, but beyond that distance, and just above the clay (Z), there 

 is a line of nodules (y) in which are numerous specimens of Ammo- 

 nites Des7im/esi, and occasionally of A. Cornuelianus ; close to these 

 nodules are others of ironstone, very similar to the masses found in 

 the Lower Greensand of Blackgang and Shanklin, in the Isle of 

 Wight, containing casts of fossils, of which I give the following list, 

 the species having been determined by Mr. Etheridge. 



Fossils from Nodules in hase of Carstone. 



Wood. 



Trigonia, sp. 



Leda, sp. 



Pecten striato-punctatus, Bcemer. 



Lucina crassa, Sow. 



Isocardia angulata, Phil, 



Nucula planata, Desk. 



Avicula macroptera. 



Pecten orbicularis, Sow. 



Cardium subhillanum, Leym. 



Pleurotomaria gigantea. 



Ammonites Cornuelianus, If Orb. 



Dentalium. 



Pectunculus. 



Terebratula biplicata, Broc. 



Dianchora. 



From this part of the Carstone I have obtained Perna Mulleti, 

 Ancyloceras gigcis, Pleurotomaria — fossils which, viewed in connexion 

 with the presence of Ammonites Deshayesl, &c., correlate the portion 

 of the Carstone immediately above the Clay (Z) with the base of the 

 English Lower Greensand. 



By a reference to the section it will be seen that the Hunstanton 

 Red Chalk is, in position, lower than the Chalk Marl (a) and higher 

 than the Lower Greensand (X, Y) ; the fossils also, it will be ob- 

 served, recorded in the hst as common to the bed, present a mixture 

 of what are generally considered Lower Chalk, Upper Greensand, 

 and Gault forms. The mingling together of these species, no less 

 than the peculiar aspect of the stratum, has long caused the Red 

 Chalk to be a fertile field for discussion in reference to its proper 

 position in the geological scale, various writers offering various 

 opinions, Mr. C. B. Rose* inclining to its being the equivalent of the 

 Gault, Mr. H. Seeley t to its being Upper Greensand, and Mr. Judd J 

 to its combining both formations. If, however, the very fine section 

 of the Gault at Folkestone (where the succession of the beds and their 

 fossils can be examined in situ) be taken as typical of the English 

 Gault, then it wiU become evident that the " Red Chalk " is the 

 representative of the upper division of that formation ; for at 



* " On the aeology of West Norfolk," Phil. Mag. 1835, vol. vii. p. 180. 



t " Notice of Opinions on the Stratigraphical Position of the Ked Lime- 

 stone," Ann. Mag. Nat. Hist. 1861, vol. vii. p. 240. 



I " Strata wliich form the base of the Lincolnshire Wolds," Quart. Journ. 

 Geol. Soc. Tol. xxii. p. 249, 18G7. 



