24 Bulletin 15 334 



Odostomia Nysti Bosq. Rissoa turbinata Defr. 



" acutuisaihim ^rQ.\in. Mytihis subfragilis A'Oxh. 

 Liicina Thierensis Heb. Dreissensia Brardi Brongn. 



Other species common in the sands are 



Buccimim Gossardi Nyst. Pleurotoma costellaria Duch. 



Cerithium elegans Desh. Natica Nysti d'Orb. 



" plicatum ^XM'g. Neritina Duchasteli TiGsh. 



" La7narcki ^xongn. PeSlunadiis lunulatiis '^ysX.. 



Fossiliferous Rupelian beds. Paleontologically, the most im- 

 portant beds of the middle Oligocene (Rupelian) are the sand of 

 Berg and the clays of Boom. Of the species in these deposits 

 some were described by Jean Kickx* in 1830. De Koninckf and 

 NystJ later published important monographs. Comparatively 

 recently M. Vincent of the Belgian survey has published a list|l 

 of the Rupelian fauna of Belgium. 



The sands of Berg. As already noted, the writer found 

 the sand pit at Berg, from which some seventy finely preserved 

 species have been obtained, closed hy order of the government. 

 Another outcrop was then visited where PeHen Hoeninghausi was 

 found to be very common, but still more abundant were the valves 

 of PeElunculus obovatus which, by their number, distinguish these 

 sands which lack markedly charadleristic species. Among other 

 mollusca reported as common in this deposit are 



Vohita rathieri Heb. Cassidaria nodosa Sol. 



Typhis cuniculosus Duch. Murex Deshayesi Nyst. 



Triton Flandricum De Kon. Fiisus multisulcatus Nyst. 



Nucula clays. The sands of Berg are followed by clays 



* Synopsis Molluscorura Brabantiae, in-4°, i pi., 1830. 



t Description des coqi:illes fossiles de Bsesele, Boom, Schelle, etc., in-4°, 

 1S37; also in tome XI Memoire de rAcademie royale des sciences et belles 

 lettres de Bruxelles, 1838. 



X Note a propos des coquilles fossiles de Boom. Bull, de la Sac. Geol. 

 de Fr., ire sen, t. XIV, p. 451, 1843; Description des coquilles et des poly- 

 piers des terrains tertiaires de Belgique. In-4°, 1845; also in Mem. couron- 

 nes de V Acad, royale de Bruxelles, t. XVII, 697 pp., 15 pi. 



II Nouvelle liste de la faune conchyliologique de I'argile rupelienne. 

 Ann. Sac. R. Malac. de Belg., t. XXIII, 1888, pp. 38-40. 



