H. W. Pearson — Oscillations of Sea -level. 253 



aud join the branches from the opposite side, each branch being 

 slightly thickened into an obtuse tubercle at the margin of the 

 periphery. On the rest of the outer whorl each rib, instead of 

 actually bifurcating, bends slightly backward at the lateral tubercle 

 and passes straight to the peripheral margin, where it is slightly 

 thickened into a blunt obtuse tubercle ; whilst in the space between 

 each pair of lateral tubercles, but somewhat nearer the periphery 

 than the tubercles themselves, an obscure rib arises and also passes 

 to the peripheral margin, where it is also similarly thickened ; the 

 tubercles on the intermediate ribs are frequently stronger than those 

 at the extremities of the principal ribs. In a few instances the ribs 

 are raised into a very obtuse tubercle on the median line of the 

 periphery. On the peripheral area of the earliest portion of the 

 outer whorl, i.e. the portion bearing the single feeble groove, the ribs 

 on one side of the median line are slightly inclined backwards, whilst 

 on the other side they are nearly direct. Although portions of the 

 septa can be seen, a complete suture-line cannot be made out, but 

 from the parts that are visible the septa appear to be fairly 

 symmetrical. 



On the whole I think there cannot be much doubt about the 

 present example being referable to Sharpens Ammonites Ramsayanits. 

 Notwithstanding the apparent symmetrj' of the specimen, its peri- 

 phery presents certain appearances which suggest that the fossil is 

 deformed. 



One side of Sharpe's specimen, viz. that represented in his fig. 4&, 

 looks something like a deformed Ammonites Salteri, ' which Sharpe 

 also described from the " Chalk with silicious grains, at Chardstock, 

 Somersetshire," but the opposite side appears to be quite dififerent. 



Sharpe's type-specimen certainly was deformed, and I think the 

 Bath specimen is also, but being unable to refer them to any other 

 species which has hitherto been described from the Chalk, it seems 

 desirable to retain, at least provisionally, Sharpe's name Ammonites 

 Bamsayanus. 



V. — Oscillations in the Sea-level. (Part III.) 



By H. W. Pearson. 



[Oontinited from the May Number, p. 231.) 



Data nsed in shoioing a Period of High Sea - level in the North, 

 culminating about the years 1475 to 1500. 



NORWICH, England, is represented as situated on the banks of 

 an arm of the sea even in the thirteenth and fourteenth centuries 

 (Lyell's "Principles," 11th ed., vol. i, p. 521; S. Woodward 2). 

 Early in the fourteenth century Pagham Harbour was formed by 

 a sudden inroad of the sea (Encyc. Brit., vol. xxii, p. 723). 



1 D. Sharpe: Foss. Moll. Chalk (Mou. Pal. Soc), pt. iii, 1856, p. 50, pi. xxiii, 

 ff. 3«, b, c, and Cic, h. 



- "History and Anti([iutics of Norwich Castle," 1836. Plates showing- the 

 ' Yarmouth Hutch Map,' a.d. 1000, aud at various other periods, earlier and later : 

 drawn from local records and ifoological observaticms. 



