OP THE UPPER CEETACEOT7S IN" WEST SUFFOLK AND NORPOLK. 597 



pits it has a tendency to form an overhanging cornice. In thick- 

 ness this part of the Lower Chalk diminishes from about 80 feet near 

 Newmarket to about 35 feet near Hunstanton. 



Belemnite Marls. — The component strata of this zone are so per- 

 sistent in the midland counties that we were not prepared to find 

 such a difference in the Norfolk sections, and, in the absence of any 

 exposures between Snailwell and Whittington, we can only say that 

 a great change takes place in the interval, and that this change is 

 in harmony with those exhibited by the other beds. It consists in 

 a diminution in the amount of the muddy ingredient, and this con- 

 densation continues till, in the north of Norfolk, the marly element 

 is almost eliminated, so that in the absence of fossil evidence it 

 becomes impossible to recognize the horizon. 



The Melbourn Rock, which forms the base of the zone of ffliyn- 

 chonella Cuvieri and of the Middle Chalk, presents substantially the 

 same characters as it possesses in the counties of Cambridge and 

 Hertford. It is evident that at this time deep-sea conditions pre- 

 vailed over the whole area, consequent perhaps upon an accele- 

 ration in the rate of subsidence, so that a deposit of the same kind of 

 sediment was formed over a large area. 



In conclusion, we would point out that the total amount of diminu- 

 tion in the thickness of the Lower Chalk between Newmarket and 

 Hunstanton is 115 feet, being the difference between 170 feet at 

 Newmarket and 55 feet near Hunstanton. In spite, however, of 

 the reduced thickness of the Lower Chalk in West Norfolk, we 

 have found that its zonal divisions can be brought into harmony 

 with those which have been established in the midland and southern 

 counties. 



This having been done, we now possess a surer basis for the 

 study of the Lower Chalk of Lincolnshire, which is known to be 

 generally similar to that of West Norfolk. The Totternhoe Stone 

 has not yet been identified in the northern counties, but the Hun- 

 stanton section shows that its attenuated representative may still be 

 found in Lincolnshire, since the Lower Chalk is certainly somewhat 

 thicker than it is near Hunstanton. 



Discussion. 



The President remarked on the difficulty of correlating a series 

 of beds which have become greatly attenuated and meet together. 

 He also commented on the difference of opinion as to the pakeonto- 

 logical evidence where the fauna is elsewhere so largely developed.. 

 There was a difference as to geological position, though general 

 agreement as to thinning. 



Mr. E. T. Newton acknowledged how much the Society was in- 

 debted to the Authors. He was not acquainted with the district in 

 question, but had at different times been consulted by both Mr. Hill 

 and Mr. Clement Eeid. Unfortunately circumstances had prevented 

 those gentlemen from meeting to discuss this question, although 

 they were desirous of doing so. With regard to the fossils collected 



