352 MR. W. HILL OX THE LOWEE BEDS OE THE UPPER 



It will be seen from the list that the fauna which characterizes the 

 Lower Chalk of Lincolnshire continues through Yorkshire, and 

 though the beds which form the base of the Chalk Marl at Speeton 

 differ somewhat from those occupying an equivalent position in the 

 western escarpment of the Wolds, the assemblage of forms contained 

 in them leaves but little doubt as to their general relations. 



The sharp lithological divisions of Eed Chalk, Sponge-bed, and 

 Inoceramus-hed are lost at Speeton, but Avicida gryphoeoides, whose 

 appearance in abundance is a special characteristic of the basement- 

 bed of the Chalk Marl in West IN'orfolk, is here also a prominent 

 fossil in a like position. Common in bed 2, it becomes abundant in 

 the base of bed 3, from which point it seems to die away gradually, 

 becoming at last associated with Lima ecMnata, Plicatula inflata, 

 and BhyncJionella lineolata, which last form appears to replace Eliyn- 

 chonella Martini as the Chalk Marl puts on its northern facies. 



Holaster subglobosus occurs from the base of bed 3 to the Belem- 

 nite-marls, with Holaster rotundus (sp. nov.) and Discoidea cylindrica, 

 the last being by no means common at Speeton. 



A species of Peltastes resembling Peltastes stellulatus appears to 

 be not uncommon in the Chalk Marl of Speeton. Prof. Wiltshire 

 records it, apparently from bed 2 ; I found a perfect specimen at 

 the top of bed 3 and another a few inches only under the " Grey 

 Bed." This last specimen, however, differs from P. stellulatus and 

 resembles P. WrigJitii in its large size and more inflated test ; and, 

 again, it differs from P. WrigJitii and resembles P. stellulatus in the 

 ruggedness and punctation of the apical disk and in having less 

 numerous and more prominent tubercles, and also in the size of the 

 mouth. Finally it differs from both the Lower Greensand forms in 

 the thickness and strength of the apical disk, by its greater height, 

 and by the much greater number of granules between the tubercles 

 of the ambulacral areas. 



Viewed as a whole, the assemblage of forms found in and below 

 the " Grey Bed " in Lincolnshire and Yorkshire agrees with that 

 from the same division in West Norfolk. This northern facies, 

 which differs from that of the Chalk Marl of Cambridge and 

 Bedford, &c., has been shown * to come on gradually as the Marl is 

 followed northward to Hunstanton. 



The similarity of the fossils of the " Grey Bed " to those of the 

 Totternhoe Stone has been already noticed. 



The assemblage in the " Grey Chalk " is such as would be met 

 with in the South of England. The abundance of Ammonites at 

 its base just above the ^' Grey Bed " in both counties is remarkable ; 

 at Speeton I counted 7 large ones in about 2b yards. 



Besides Belemnitella 'plena I found nothing in the Belemnite- 

 marls but fish-scales. 



In the overlying Middle Chalk a very short search usually dis- 

 closed the commoner species met with at this horizon, viz. : Ino- 

 ceramus mytiloides, Wiynchonella Cuvieri, and Echinoconus suhrotun- 

 dus. The first is abundant everywhere about 6 feet above the 

 * Quart. Journ. Geol. Soc. vol. xliii. p. 576. 



