CEETACE0T7S SERIES IN LINCOLNSHIRE AND TORKSHIRE. 



345- 



which from South Lincolnshire to Leavening in Yorkshire has 

 formed a fairly marked basal bed of the Chalk Marl, is gone, and its 

 place taken by rough, nodular, and coloured chalk, unlike any which 

 occurs at this horizon elsewhere in England. The thickness of this 

 bears a close relation to the accession in the thickness of the Chalk 

 Marl. Avicula grijpliceoichs^ a characteristic fossil of the beds sepa- 

 rating the Gault and Chalk Marl both in Bedfordshire and West 

 Norfolk, is abundant. 



There is no marked line of division in the lower beds excepting 

 colour, the material of the Eed Chalk graduating into the Chalk 

 Marl, and this into gritty chalk at the top of bed 3 and base of bed 4, 

 and this, again, passing away upwards. 



The " Grey Bed " forms a well-defined line at the summit of the 

 Chalk Marl, and above it the Chalk, differing slightly in minor points, 

 presents much the same characters and sequence which become 

 familiar to anyone following the outcrop of these beds along the 

 Wolds of Lincolnshire and Yorkshire, while its thickness throughout 

 is remarkably uniform. 



The three Echinoderms, Holaster suhglohosus, Holaster rotundus^ 

 (sp. nov.), and Discoidea cylindrica occur throughout the Lower 

 Chalk in the Speeton Cliffs. 



The entii-e section of the Speeton Cliffs is as follows : — 



Middle Chalk. 



Zone of 

 Bel, plena. 



Grey Chalk. 



"Grey Bed" 



= Totternhoe 



Stone. 



Chalk Marl. 



Gault 



ft. in. 



/'Hard white chalk, with flints 



I Bedded whitish chalk, very hard and crystalline 



•{ {Inoc. mytiloides) 5 



I Courses of creamy white chalk, about 6 inches thick, 



\ divided by buff marl bands 2 6 



r Band of shaly marl, variegated, bluish grey or buff ... 4-6 



J Hard, smooth, white chalk 1 Q 



1 Shaly marl, almost a clay, paler bluish grey at the 



[_ edges, almost black in the centre 9 



^Eubbly chalk passing down into smoother and more 



compact material 1 



Compact whitish chalk, smooth on the whole, in 

 courses, a marked massively bedded layer at the 



base 21 



Eough, nodular, or lumpy chalk, with well-marked 

 marl bands, the marl separating the lumps some- 

 times in excess ; colour varied, the base is, in some 



places, stained pink 20 



A marked course of grey-coloured chalk, rather no- 

 dular, graduating at its base into a marked marly 



band 2 



''Eather rough chalk, with smoother courses inclining 

 to become nodular at its base, where the marl 

 bands and chalk become more gritty. The top of 



this bed is sometimes stained pink 39 



^ Eather nodular or lumpy chalk, this character be- 

 coming more pronounced downwards. Material 



coloured pink and white in alternate bands 28 



^ Bluish-grey nodular chalk, with marl bands 10 



Eed Chalk or Hunstanton Limestone 30 



