1926 SYSTEMATIC 25 



excluding it from the genus Shotoverites ; but there can be no hesitation 

 in saying that its SI. • formula shows it not to be Wheatleyites — for its 

 EL and Li are some 20 per cent, too short (see this Vol., p. 9). Therefore 

 Pruvost's pringlei runs considerable danger of clashing generically with 

 Shotoverites pringlei, with which, however, it is not conspecific. The 

 likeness is sufficiently strong to suggest that the La Rochette 

 phosphate bed of the Boulonnais may be isochronous with a lower part 

 of the Shotover Sands (Paravirgatitan). This is, in spite of all that 

 has been written about the correlation of English and Boulonnais Port- 

 landian strata, one of the very few points where the Ammonoid fauna, 

 as at present known, suggests synchronism. 



By the kindness of Dr. Dutertre, Boulogne Museum, I have been 

 able to examine a considerable series of Ammonoids from the Port- 

 landian-Kimmeridgian strata of the Boulonnais. Striking is the lack 

 of identity between the fossils of the Boulonnais and the English areas 

 — those of the Midlands and Dorset coast. But more agreement may be 

 found when the Ammonoid faunas of the two countries are better 

 illustrated and better understood — especially may the south-east English 

 area (Kent coalfield) be expected to help. But at present the Boulonnais 

 area seems to have the largest number of gaps, lacking many of the 

 Ammonoid elements so conspicuous in England. On the other hand 

 there are Boulonnais Ammonoids not yet seen in England, though some 

 may be expected from certain English beds where specimens are badly 

 preserved. 



No surprise need be felt at this lack of identity, when the same 

 phenomenon is to be seen in closely contiguous Portlandian-Kimmeridgian 

 areas in England. For instance, the Hartwell Clay Ammonoid fauna, 

 Holcosphinctes, Aposphinctoceras and Episphinctoceras have only been 

 found very locally in England, and no trace of them has yet been seen 

 among the Ammonoids of the Boulonnais. 



Lastly, Dr. Neaverson's Pallasiceras pringlei is a species quite 

 distinct from Shotoverites pringlei or from " Wheatleyites " pringlei. 

 It is of later date, coming from the beds of Chapmans Pool (Paravirga- 

 titan, lyditicus) ; but the author does not give a suture-line to enable 

 the reader to decide whether the genus be Pallasiceras or Lydistratites. 

 However, the Officers of the Geological Survey have most kindly sent 

 me their examples of his types, and it can be said the Neaverson's 

 Pallasiceras pringlei is generically correct, possessing the short lobes 

 of the genus. 



In regard to the species attributed by Dr. Neaverson to the genus 

 Aposphinctoceras, mentioned above as from Hartwell Clay, there is much 

 trouble. The genotype is a species from the Littleworth Lydite Clay 

 (Paravirgatitan 8, T.A. Ill, 26) of Chippinghurst, near Chiselhampton, 

 Oxfordshire (M. Healey, Jur. Amm. ; Q.J.G.S., Ix, 1904, 61, PI. xii, 

 Olcostephanus pallasianus ; Neaverson, Geol. Mag. Ixi, 1924, 149, 

 Aposphinctoceras decipiens, name given to Healey's figures), and it is 

 doubtful if it is generically different from the prior-named Lydistratites. 

 But the Hartwell-Clay species, which, I contend, are of much earlier 

 date (Pseudovirgatitan 3, T.A. Ill, 33), Dr. Neaverson has put into 

 his Aposphinctoceras (op. cit 11, 3-5 — Ap. alleshuriense, hartwellense, 

 variabile). These Hartwell species are not claimed by Dr. Neaverson 

 as conspecific with the Chippinghurst species, and it is obvious that 



