76 ME. G. w. LAMPLraii ON THE ju:n^ctiox of [vol. Ixxviii, 



until the ferruginous induration of the Shenley shoal provided a suitable 

 habitat. This was soon occupied in force by T. capillnfa and its congeners : 

 and they throve there until the oncoming of the Gault clay-conditions, which 

 put an end to them in this place. The Gault is notoriously poor in brachio- 

 pods, particularly the Lower Gault clays, which usually contain none. This 

 species and the Terehrirostra. among others, evidently reached their acme at 

 about the beginning of the Gault period, although they lingered for some 

 tim.e longer before extinction. 



EcHixoDERMATA (p. 48). — The list of the Shenley fossils of this Class is 

 suggestive of a horizon above the Gault, but the anomaly is not so tangible 

 in reality as in print. The only material, except a few sjDines and other 

 fragments in my own collection, is the Walker collection at Cambridge, 

 containing about a score of ill-preserved tests and some spines, which are 

 acknowledged to be generally too poor for confident determination.^ and 

 where confidence can be expressed, it is based on one, two, or at the most 

 three, specimens. Our original list (L.W., p. 263) comprised four positive 

 specific identifications : one of these has been reduced by a P and another by 

 an aff, as the result of the recent expert re-examination. Without venturing 

 to question the authoritative determinations, I will submit some comments 

 on the species, which appear to be pertinent. 



The echinoid fauna of the Gault clays is scanty, and of a different facies 

 from the shallow rock-reef fauna of Shenley. The English deposits, therefore, 

 have hitherto provided us with little or no information as to the ancestry and 

 progress of the echinoid ' reef -facies ' during and just before the period of the 

 clay-sediments. The Tourtias of the Continent, however, contain many relics 

 of this facies ; and it is in them, and not in the English beds above the Gault, 

 that comparisons with the Shenley forms should be sought and may, I think, 

 be found. 



Catopygus columharius (sl single specimen), one of the smaller echinoderms, 

 is (I believe) regarded as of prime consequence in the argument for the post- 

 Gault age of the limestone. In the West of England it is a well-known fossil 

 of the top beds of the Upper Greensand and the lowest part of the Lower 

 Chalk : but a very similar fossil occurs in the Lower Greensand, and is recorded 

 as C. carinatus Goldfuss (supposed to be a synonym of C. coJiimhariiis) from 

 the Hythe Beds of Hythe.- C. carinatus is also recorded from the lowest 

 zone of the Albian of the South of France, from beds which we should class 

 as Lower Greensand.^ C. columharius is a common fossil in some of the 

 Tourtias,"* and a form near to it is recorded from the ' Sables Yerts de Denne- 

 broecq ' occurring in association ynth Ammonites tardefurcatus and other 

 fossils of the jNIammillatus Beds.^ The type, if not the actual species, appears, 

 therefore, to have been in existence before the period of the Gault clays. 



Niicleoliteslacunosus Goldfuss (1 specimen), another small echinoderm, ' one 



^ H. L. Hawkins, ' Note on a Collection of Echinoids from the Limestone- 

 Lenticles in the Sand-Pits of Shenley Hill' Geol. Mag. 1921. pp. 57-60. 



" ' Geology of the Weald ' Mem. Geol. Surv. 1875, p. 413. 



3 C. Jacob, ' Etudes, &c. sur la Partie Moyenne des Terrains Cretaces, &c.' 

 (op. cit. antea. p. 49). 



^ A. d'Archiac, ' Sur les Eossiles du Tourtia ' Mem, Soc. Geol. France, ser. 2, 

 vol. ii (1874) pi. xiii, and G. Cotteau, 'Note sur les Echinides Cretaces de la 

 Province du Hainault ' Bull. Soc, Geol. France, ser. 3, vol. ii (1874) p, 652. 



^ H. Parent, ' Sur I'Existence du Gault, &c.' Ann. Soc. Geol. Nord, vol. xxi 

 (1893) p. 218. The fossil is recorded as ' Catopygus cf. cylindricxis'De^or ,' with 

 an appended note by M. Lambert : ' Cette espece se rapproche surtout des 

 C. carinatus Agassiz du Cenomanien et C. cylindricus Desor de TAlbien,' &c. 

 A. J. Jukes-Browne in his ' Gault ' memoir {op. supra cit. p. 477) places 

 C. carinatus as synonjTnous with C. columharius. C. cylindricxis is a charac- 

 teristic echinoderm of the Upper Aptian of the South of France (see W. Kilian, 

 op. supra cit. pp. 309, 362). 



