A. J. Jukes-Browne — Division of Upper Chalk. 165 



Mr. Brydone himself. It seems that A. granulatus is a rare fosgil in 

 Hants and Wilts, but that does not prevent it from being a useful 

 guide elsewhere, and Mr. Rowe's experience, as stated in his successive 

 studies of the cliff-sections, is that it always occurs in the lower half 

 of the old ' quadratus zone ' and does not range to the top of that zone, 

 where quadratus usually occurs. Does Mr. Brydone mean to deny 

 this ? if so, let him say so and prove it, but he has no right to find 

 fault with me for compiling lists in accordance with what has hitherto 

 been regarded as an established fact. 



The only published record of ^, granulatus in the highest part of the 

 zone is that for which I am responsible, as mentioned by Mr. Brydone, 

 viz. in a quarry at Bramford, near Ipswich, where Belemnitella 

 mucronata was afterwards found. That determination was made 

 in 1902 and I cannot remember what the specimen was like, but 

 I should not now like to maintain that it was granulatus without 

 a second examination of it. The quarry may possibly expose the 

 junction of the zones of A. quadratus and B. mucronata. 



We come next to the Yorksliire Chalk, and I am told that I had no 

 right to assume that the Yorkshire cliffs do not include any chalk of 

 the restricted zone of A. quadratus. I have undoubtedly assumed 

 tbat all the chalk in these cliffs and most of that inland belongs to the 

 equivalent of the new zone of 0. pilula, but I did not do so solely 

 because true A. quadratus had not been found in the Sewerby cliffs. 

 1 relied on the positive facts (1) that A. granulatus is abundant 

 throughout the exposed portion of the zone, and (2) that the 

 thickness exposed in the cliffs is only 177 feet, whereas the total 

 thickness of the whole zone of A. quadratus (so-called) must be 

 about 400 feet. 



The only place where a true A. quadratus has been found is the 

 White Hill Quarry, No. 27 of Mr. Rowe's list and map, situate north 

 of Bridlington and about 200 feet above the sea. An inspection of 

 the map above mentioned will show that if 177 feet of chalk come 

 into the Sewerby cliffs there must be some 340 feet of chalk between 

 the basal outcrop of the zone and White Hill Quarry. Further, 

 as Mr. Brydone has himself pointed out, the mere presence of 

 A. quadratus does not itself prove that the restricted zone of that 

 fossil has been reached. Hence the White Hill pit may still be 

 within the limits of the lower zone, and, as Mr. Stather informs me 

 that S. hinodosus is fairly common in this pit, such a position seems 

 very probable, for in Germany S. hinodosus is only found in the 

 ' gi'anulaten kalk', and not in the German zone of A. quadratus. 



Belj'ing, therefore, on the association oi A. granulatus ^x\^ O.pilula, 

 as well as on the absence of A. quadratus, throughout the Sewerby, 

 Bessingby, and Carnaby areas, I felt justified in regarding this 

 Yorkshire zone of A. granulatus as the equivalent of the German 

 zone of >S. hinodosus and of Mr. Brydone's zone of 0. pihda. If 

 there is really any difference between the Yorkshire and the 

 Hampshire zones, it is not (as Mr. Brydone suggt^sts) that some 

 of his higher zone may come into the Yorkshire cliffs, but that the 

 Yorkshire zone of A. granulatus represents a larger portion of the old 

 zone of A. quadratus than his zone of 0. pilula does in Hampshire. 



