in the South English Chalk. 



511 



relates to A. graiiulatiis it is presumably based on the Belemnite 

 mentioned by Dr, Rowe ^ as found 150 feet above the zone of 

 Marsiipites. But Dr. Howe does not state that this Belemnite was 

 identifiable as A. granulatus ; on the contrary, lie states that it was 

 not identifiable, biit was considered to resemble A. quadratus and to 

 be likely to be that species. Clearly, therefore, Mr. Jukes-Browne's 

 test, even if a sound one, does not justify his assigning 150 feet 

 positively, with a further 20 feet, as stated by him (really about 

 50 feet), by inference to his zone of O.pilula. On the other hand, the 

 two specimens of A. granulatus 120 feet above the zone of Slamupites, 

 recorded by Dr. Howe on the same page, compel the assignment to 

 Mr. Jukes-Browne's zone of 0. pilulaa minimum thickness of 120 feet. 

 This is already 15 feet more than can respond to my zone of O.pilula, 

 and the discrepancy is liable to be increased at any moment by the 

 finding of A. granulatus at higher levels. The truth is that the 

 granulated Belemnites are too scarce in South England in the middle 

 of the old zone of A. quadratus to be treated as normal constituents 

 of the fauna, when the enormous area exposed at this horizon in the 

 cliffs of Sussex and inland in Hants is considered. At the moment 

 of writing there are only thirteen accxxrately zoned and reliably 

 identified specimens known to me from Hants and Sussex. They are 

 distributed as follows: — 



Note. — Two of the Sussex Belemnites have been found since the Sussex 

 section of the paper went to press. 



To these it may be added on Dr. Blackmore's authority that at 

 Salisbury A. granulatus is not yet known at any of these horizons, 

 which have been extensively worked, but two specimens of 

 A. quadratus have been found in the lower belt and three in the 

 middle belt of the subzone of abundant 0. pilula. while in the upper 

 belt of this subzone A. quadratus becomes definitely an established 

 member of the fauna. Now that the range of this upper belt of 

 the subzone has been established at Mottisfont, where it undoubtedly 

 contains a fair number of granulated Belemnites, there should very 

 soon be further evidence available from there. 



Obviously the material is at present hopelessly inadequate to 

 support even in theory the establisliment of a zonal boundary for 



^ Coast Sections, i, p. 343. 



