CRETACEOUS SERIES IN LINCOLNSHIRE AND YORKSHIRE. 341 



On Greet's Hill, above Acklam, a section showing 16 feet of " Grey 

 Spongy Chalk" has been given on page IV35. 



The next exposure of the Lower Chalk is at Leavening ; the cir- 

 cumstances connected with the exposure are to be found on page 333. 

 The section is as follows : — 



Descending, 

 ft. in. 

 Chalk rubble, showing no pink colour, much broken up 6 

 ^Whitish chalk, not hard, much broken but apparently in 

 rt ni n J place, irregularly bedded, with strongly marked buff- 



GreyChalk. j ^olouVed bauds of marl.... 9 



\^ Whiter chalk less marly than hard 2 6 



The f Hard nodular chalk, grey in colour, clearly distinguish- 



"GreyBed."! able from that above or below 2 



^Hard whitish chalk, more massively bedded than the 



underlying, and less rough 9 6 



Thin-bedded chalk, rather rough and nodular, weather- 

 rhalk M 1 -l ^"» ^^^^ ^^^^ platy pieces — a marked marly band 



j divides this from the course above 8 



Hard, very gritty, massively bedded, greyish-white chalk 6 

 { Hard, crystalline, reddish-yellow limestone, seemed 



1^ sharply marked from the chalk above 1 



Gault Red chalk, passing down into next 2 



{Yellowish-brown sandy material, with quartz and dark- 

 coloured oolitic grains and nodules of ironstone show- 

 ing oolitic structure about 6 



A yard or two beyond the point where the section ends, rubble of 

 pink chalk is seen, but its relative position with regard to the re- 

 mainder of the section is not determinable, nor, as will be seen 

 presently, is the position of a colour-band an important point. 



It seems to me impossible to consider the sequence of the beds here 

 and not see that there is a repetition of the succession in the cutting 

 east of South Cave and also of the Lower Chalk of Lincolnshire *. 

 Red Chalk, Sponge-, and /wocgr«?7nt5-bed, followed, after an interval 

 of smoother and whiter chalk, by a marked grey-coloured bed, over- 

 lain by marly chalk with marked buif-coloured bands, is a recurrence 

 of the succession seen from south to north. 



Between the cuttings east of South Cave and this place there is a 

 diminution in the thickness of the equivalent of the Chalk jVIarl of 

 6| feet, an attenuation shared in a greater degree by the E-ed Chalk. 

 There are grounds for considering this decrease in the thickness of 

 the Red Chalk gradual, and the cause of it was probably not without 

 its effect on the beds above ; but judging from the uniformity of 

 thickness of the Grey Chalk and its apparent freedom from influences 

 which we shall shortly see affect the equivalent of the Chalk Marl, 

 I consider the chalk above the " Grey Ued " to be but little thinner, 

 and estimate the entire thickness of the Lower Division of the Chalk 

 to be at this point not less than 60 feet. 



Pollowing the outcrop northwards, yellowish marly chalk is seen 

 along Birdsall "Wold, about | of a mile west of Swinham, probably 

 that above the " Grey Bed." About ^ mile east of this place, 

 pink chalk occurs above a bed of grey-coloured chalk very like that 



* See Section V. page 366. 



