Geological Society of London. 329 



A few notes were added on the relations between this fauna and 

 that now inhabiting the Australian seas, also on the connexions 

 with the Tertiary Echinoidea of New Zealand, Sind, etc. 



2. " On the Lower Part of the Upper Cretaceous Series in West 

 Suffolk and Norfolk." By A. J. Jukes-Browne, Esq., B.A., F.G.S., 

 and W. Hill, Esq., F.G.S. 



The district described in this paper is that of West Suffolk and 

 Norfolk, and is one which has never been thoroughly examined ; for 

 no one has yet attempted to trace the beds and zonal divisions which 

 are found at Cambridge through the tract of country which lies 

 between Newmarket and Hunstanton. Until this was done the 

 Hunstanton section could not be correlated definitely with that of 

 the neighbourhood of Cambridge. It was the authors' endeavour to 

 accomplish this, and the following is an outline of the results 

 obtained by them. 



The paper was divided into six parts : — (1) Stratigraphical, (2) 

 Palceontological, (3) Microscopical, (4) Chemical Analyses, (5) Faults 

 and Alteration of Strike, (6) Summary and Inferences. In the first 

 four parts separate lines of argument were followed, and each led 

 to the same set of conclusions. 



The chief interest of the paper probably centres in the Gault, and 

 its relation to the Chalk Marl and the Red Chalk. Quite recently 

 the very existence of Gault in Norfolk has been disputed, but the 

 authors think the facts they adduce and the fossils they have found 

 will decide that point. The Gault at Stoke Ferry is about 60 feet 

 thick, and in the outlier at Muzzle Farm Ammonites interruptus occurs 

 plentifully in the form of clay-casts with the inner whorls phos- 

 phatized. At Roydon a boring was made which showed the Gault 

 to be about 20 feet thick, the lower part being a dark blue clay, above 

 which were two bands of limestone enclosing a layer of red marl, and 

 the upper 10 feet were soft grey marl; the limestones contained 

 Amm. rostratus, Amm. lautus, Inoceramus sulcatus and Inoc. concen- 

 tricus (?), while the marls above contained Belemnites minimus in 

 abundance. At Dersingham another boring was made which proved 

 the grey marl (2 feet) to overlie hard yellow marl, passing down into 

 red marl which rests on Carstone. The grey marl thins out north- 

 ward, and as the red marl occupies the position of the Red Chalk, 

 the authors believe them to be on the same horizon, an inference 

 confirmed by the presence of Gault Ammonites in the Red Chalk. 



Another point of importance is the increasingly calcareous nature 

 of the Gault as it is followed northward through Norfolk. This 

 was regarded as evidence of passing away from the land supplying 

 inorganic matter, and approaching what was then a deeper part of 

 the sea ; this inference is borne out by the microscopical evidence. 



As regards the Chalk Marl, it also becomes more calcareous : at 

 Stoke it is still over 70 feet thick, and its base is a glauconitic marl 

 which can be traced to Shouldham and Marham, but beyond this 

 the base is a hard chalk or limestone, which is conspicuous near 

 Grimston and Roydon, and passes, as the authors believe, into the 

 so-called " sponge bed " at Hunstanton. 



