356 ME. W. HILL Olf THE LOWEB BEDS OE THE UPPEE 



it, these becoming less abundant in the smootber part at tbe top. 

 The matrix becomes gradually more calcareous upward, but the 

 fine inorganic material and larger quartz particles are not entirely- 

 lost, even in bed 2, and not until bed 3 is reached does the deposit 

 appear purely calcareous. 



It has already been noted that the material of the beds over 

 which the Eed Chalk was deposited is invariably worked up, and 

 fragments incorporated at its base. The Red Chalk at Speeton 

 rests on blue clay, and in the specimen which I obtained, as near 

 its base as possible, fragments of a bluish-grey colour are included. 

 These appear to be made up entirely of very fine inorganic material, 

 are free from calcareous atoms, and are doubtless derived from the 

 underlying clay. 



Chalk Marl. — The material of the Sponge-bed, which has been 

 taken as the true base of the Chalk Marl, is, in Lincolnshire, very 

 similar to that of the Eed Chalk. In Yorkshire, though, as a rule, 

 defined by its lighter colour, as the Eed Chalk thins to the northward 

 it becomes practically inseparable from it. 



As in J^orth-west J^orfolk, the Sponge-bed is overlain in Lincoln- 

 shire and along the western escarpment of the Yorkshire Wolds by 

 the grey-coloured and gritty Inoceramiis-hed. The grittiness is pro- 

 duced for the most part by the abundance of prisms of Inoceramus- 

 shells, and gradually passes away upwards. Large glauconitic grains 

 are abundant at the base of this bed, but I have detected no other 

 mineral particles. 



Above this the deposit, as a whole, is purely calcareous, consisting 

 for the most part of amorphous material in which Poraminiferal 

 cells and entire tests, with shelly fragments, are present in varying 

 proportions. 



In the section at Speeton, except for the small proportion of 

 inorganic matter in bed 2, the deposit which immediately follows 

 the Eed Chalk appears purely calcareous, and difiers in no important 

 particular from the general structure of the Chalk Marl of Yorkshire. 

 The single Foraminiferal cells form a considerable part of the material 

 in bed 3, and I would note that in the coloured part of this bed I 

 see nothing exceptional in their appearance and preservation as com- 

 pared with those in the uncoloured part of the chalk. In the upper 

 part of bed 3, and at the base of bed 4, thin bands and veins of coarse 

 shelly material occur, which, besides a grittiness of the chalk at 

 this horizon, remind one of the Inoceramus-'hQdL. Although the 

 general character of the chalk here will hardly compare with 

 specimens from the Inoceramus-\)Qdi obtained along the western 

 escarpment of the Wolds, yet the presence of glauconite-grains, 

 which I have seen only at this horizon at Speeton, leads me to think 

 that the base of my bed 4 is really the horizon of the Inoceramus- 

 bed. 



The Grey Bed. — The Grey Bed which has been followed through 

 Lincolnshire and Yorkshire, forms, like its amplified equivalent in 

 Bedfordshire and Cambridge, a break in the steady deposition of the 

 chalky mud. It would appear that a slight current carried away the 



