OF THE UPPER CKETACEOUS IN" WEST SUFFOLK AND NOKFOLK. 553 



Coprolite-pits between Cambridge and Soham, is a soft, argillaceous, 

 bluish or greenish-grey marl, containing many small Brachiopoda. 



The Totter nhoe Stone is invariably found at the top of the Chalk- 

 marl throughout Buckinghamshire, Bedfordshire, and Cambridge- 

 shire ; and the most northerly point to which it has hitherto been 

 traced is the village of Burwell, in Cambridgeshire, where there are 

 large quarries and good sections. These have been described in the 

 " Geology of the neighbourhood of Cambridge " (Mem. Geol. Survey), 

 so that a brief summary need only be given here. The stone is gene- 

 rally spoken of as a grey sandy chalk, but the roughness and apparent 

 sandiness is probably due in great part to the quantity of the com- 

 minuted fragments of Inoceramus-shelh which it contains. Its 

 basement-bed is a remarkable stratum, consisting of hard, grey, 

 gritty stone full of green-coated phosphatic nodules, which vary in 

 size from that of a pea to that of a walnut or small potatoe ; the 

 thickness of this layer is from six to twelve inches and it is locally 

 known as " brassil." At Burwell the uppermost bed of the stone 

 is a course of compact grey freestone, about 3 feet thick, which 

 is known as the " bond " course and forms the best building-stone 

 of the quarries. The whole thickness of the Totternhoe Stone is not 

 exposed in any of the sections, but is seen to be more than 13 feet. 



The first locality beyond Burwell where we found traces of this 

 stone was in the shallow cutting on the new railway nearly a mile 

 north of Eordham Station. Much water is thrown out here, and as 

 a level piece of ground has been left by the removal of material 

 between the rail and the road, shallow trenches have been dug to 

 facilitate the escape of the water ; these excavations expose a 

 portion of the basement-bed of the Totternhoe Stone, which is full 

 of green-coated nodules like those of Burwell, and contains some 

 fossils, such as Pecten flssicosta, Eth., and Rhynclionella Grasiana, 

 d'Orb. Only the bared outcrop of this bed is seen, and it probably 

 dips eastward, the general features of the country suggesting that 

 the long ridge on which the eastern part of Fordham stands coincides 

 with a shallow synclinal trough. The cutting north-east of this point 

 is chiefly through a kind of chalky wash overlain by a gravelly soil. 



The " clunch-pit " three furlongs N.E. of Eordham Church appears 

 to be in the top of the Chalk-marl, just below the horizon of the 

 Totternhoe Stone ; but we found fragments of the stone near the 

 windmill three quarters of a mile N.N.E. of this, so that the hill east 

 of the mill is probably an outlier of grey chalk based on the Stone. 



At Isleham there are two large quarries, which have been worked 

 for many years ; both of these show sections of the Totternhoe Stone, 

 ver}' like those of Burwell, but the base is not exposed and there is 

 no bed comparable to the "bond course " of that locality. The 

 beds seen in the oldest quarry south of the church are : — 



Soil and rubble 



Firm greyish-white chalk 



Hard grey chalk mottled with darker grey in thin 



feet. 

 2-3 

 4-6 



beds and known as " the hards " ... 

 Grey stone in massive blocks, seen for 



2-3 

 •6 



