Spath — Ammonites from the Gingiii Chalk. 55 
bed, with Morioiiiceras texanum^ now also known from England, 
no Pachydiscids liave been recorded by Grossouvret but Yabe| 
mentioned what may be a Eupachydiscus even from the supposed 
Lower Senonian Himenoura Group, wliere perhaps Noivakites {vaju 
group) are likely to occur. 
The genus Pachydiscus^ it should be added, is here used (as 
in previous publications, and as listed in Diener ’s [5aJ Catalogue) 
to cover only the group of P. pcrampliis IMantell sj). Since Gros- 
souvre, however, in 1893§ restricted Pacliydiscus to the group of 
P. neiihergicus Hauer sp. (now Parapachy discus Hyatt) our use 
of the term^ is not in conformity with the law of priority in 
palaeontological nomenclature and can be justified only on grounds 
of universal sanction. 
t ‘‘Les Ammonites fie la Craie i^iiiierienre.' ' Reelierrlics siir la Craie Sup. 
II.. Mem. Carte Ge)I. T)et. France. 189:i. p. 2:37. 
t Fossilium Cataio<!,'US. I., pt. 29 Ammon. Noocretac, 192.5, p. 104. 
§ Loc. fit. ]). 177, alf^o * nSur L’Annnonites poram])Ius et (luelfiues aulres 
foHsiles Turoniens.’’ Rul. Soc. (tcoI. France (0), vol XXVTI. 1899. 
p. 328. 
Spath: ‘‘S'^nonian Ammonoidea from Jamaica.'' 
pp. 29-30; also Geo!. Ma?., Feb,. 1926. 
Geol. May;., Jan.. 1925, 
