Sir H. H. Howorth — Geological History of the Baltic. 457 



In a few instances we find that these shells have occasionally 

 wandered somewhat south of the Arctic Circle, but generallythe 

 more southern specimens are dwarfed and distorted. 



These deposits of Arctic shells have been named after a very 

 characteristic Arctic mollusc formerly known as Yoldia arctica and 

 now as Portlandia arctica. 



It is only lately that the widespread occurrence of the Yoldia in 

 the raised beds of Scandinavia has been ascertained. Hisinger was 

 the first to find it in Scandinavia at Aker in West Gothland in 1837, 

 while Torell found it in a submarine clay at Varberg in 1848. It 

 was found on the shores of the Malar Sea in 1852. Sars found it in 

 Southern Norway in 1861 and described it from there in 1863 and 

 1865. Presently Esmark found it on the west side of the Bight at 

 Sandefjord and Ranviken. It was Brogger, however, who added 

 so greatly to the number of its known sites, thirty of which are now 

 known. Of these he enumerates twenty-four from the Cliristiania 

 Fjord (op. cit., 669-70). He gives full details with a map on 

 pp. 8-54 to the same work. 



At Wenersborg A. Lindstrom found the shell and other shells, 

 while at Gothenburg Torell met with it a few metres above the sea; 

 V. Munthe found the same shell at Kollekan and on the island of 

 Tjorn in Bohuslan, in the former case at a height of 5 to 7 feet and 

 in the latter at 10 feet above the sea-level. With it occurred 

 Pecten islandicus, Portlandia arctica, Macoma {Tellina) calcarea, and 

 Saxicava rugosa. 



Crossing over the Cattegat we have a similar set of beds which 

 have been described by Johnstrup, V. Madson, and A. lessen from 

 Vendsyssel, that strip of North Jutland forming a long narrow 

 peninsula separated from the mainland by the Limfjord. The species 

 found in the Yoldia beds of this district consist of Modiolaria discors, 

 JVticula tennis, Leda pernula, Portlandia arctica, P. lenticula, Axinopsis 

 orbiculata, Aximis flexiiosus, Macoma calcarea, M. mosota, M. crassula, 

 Lyonsia arenosa, My a truncata, Saxicava pholadis, Natica sp., Bela 

 nobilis, Trophon clathrattis, Buccimim Groenlandicum, Neptunea despecta, 

 Cylichna Reinhardti, Utriculus perteniiix. On this list Brogger 

 comments thus: The commonest species are Saxicava pholadis, 

 Portlandia arctica, Modiolaria discors, Macoma calcarea, M. crassula, 

 and Cylichna Reinhardti. 



All these species, with the exception of Axinopsis orhiculata, are 

 living in the Kara Sea and also in the Greenland seas. Tlie fauna 

 from Vendsyssel, he continues, has the same Arctic character as that 

 of the Yoldia beds of the Christiania Fjord, although not quite the 

 same species. Jessen has found the Yoldia clay in this district as 

 high as 33 metres. 



In the island of Laeso in the Cattegat, according to Jessen, the 

 same high Arctic species have been found at an elevation of 3 metres 

 and more. From Halland and Dalshmd in Western Sweden the 

 Yoldia beds have long been known. Hisinger was the first to find 

 Yoldia at Akersvass and Trollhatten, and with it a number of other 

 molluscs from 12 to 15 metres or 40 to 50 feet ai)Ove the sea-level. 



In Western Norway Torell found it in 1860 at Lademoen and 



