Sir H. H. Howorth — Geological History of the Baltic. 403 



fundamental and much more important. This consists in the 

 presence in the northern part of a series of raised beaches of an 

 entirely separate class and which have not appeared in these papers 

 before. They are the so-called Yoldia beds. These beds have been 

 much misunderstood. I shall postpone their consideration for the 

 present and will now limit myself to the other class, namely, the 

 Tapes \)Q^s, wliich occur here associated with a much richer fauna 

 than they do in the southern part of the Cuttegat. The greater 

 richness in forms of these more northern beds must not allow us, 

 however, to disguise the fact that they are otherwise quite continuous 

 "with the Tapes beds further south, and are earmarked by the 

 presence of the same critical species. 



In regard to the mollusca found in these Tapes beds of the northern 

 Cattegat, a long list has been given by Erdmann, who says they do 

 not occur there at a higher level than 100 to 150 feet, and are for 

 the most part of littoral species. They are found in deposits of the 

 so-called black clay (svartlera), in raised beaches and sometimes 

 capping some of the dsar as in Eastern Sweden, but contain a much 

 richer number of species and were clearly deposited under conditions 

 of greater saltness in the water than those further south. 



Erdmann, in his account of the Quaternary deposits of Sweden, 

 gives the following list of the shells found in the black clays : — 



Gasteropoda. 

 Litorina litorea. 

 L. rudis. 

 L. littoralis. 

 Trochus cinerarius. 

 T^ tumidus. 

 Natica nitida. 

 N. Montagui. 

 N. clatisa. 

 N. Groenlandica. 

 N. pulchella. 

 N. borealis. 



Emarginula reticulata. 

 Lacuna vineta. 

 L. pallidula. 

 Turritella communis. 

 Cerithium reticulatum. 

 C. adversum. 

 Odostoniia rissoides. 

 Purpura lapillus. 

 Nassa reticulata. 

 N. incrassata. 

 N. pygmcea. 

 Aporrhais pes-pelicani. 

 Buccinum undatum. 

 Fusus undatus. 

 F. despectus. 



Trophon clathratus, \sir. minor. 

 Mangelia linearis. 

 Rissoa ebriata. 

 B. labiosa. 

 B. ulvcs. 

 B.parva. 

 B. istrea. 



B. arctica. 

 Patella vulgata. 

 Acmcea virginea. 

 Lepeta cocca. 

 Pallidum rubellum. 

 Dentalium {Antalis) entale. 

 Puncturella Noacina. 

 Peliscus commodys. 

 Philine quadrata. 

 Tornatella tornatilis. 

 Cylichna cylindracea. 



C. truncata. 



Lamellibeanchia. 



Mytilus edulis. 

 My a truncata. 

 Modiola modiolus. 

 Solen ensis. 

 Cyprina islandica. 

 Nucula nucleus. 

 Leda pernula. 

 L. caudata. 

 Cardium edule. 

 C. echinatum. 

 C. fasciatum. 

 C. Norvegicum. 

 Lucina borealis. 

 Montacuta bidentata. 

 Isocardia cor. 

 Pecten islandicus. 

 P. maximus. 

 P. septemradiatus. 

 P. striatus. 

 P. pusio. 



