394 
we examine onlj a part of the reports on this subject, we will find 
this interpretation not to be a true one. On the contrary, the dis- 
crepancy is very common, and this would have beeu still more evident 
if the writers of the molluscs from the great deep-sea expeditions: 
„Porcupine^', „Challenger“, „Travailleur“, and „Talisman“^ 
in their statements about the bathymetrical distribution of the species, 
had distinguished between the living molluscs and the dead shells. 
As a rule, however, they have omitted this. 
The tract for which the named occurrence of dead shallow- 
water shells at great depths has to be discussed in the first place 
is a part of the North Polar Basin, between Spitzbergen, Green- 
land, Iceland and Norway. 
In the excellent work of Prof. J.W. Brøgger: „Nivåforandringer 
i Kristiauiagebetet“ a description of this phenomenon is given, 
based on the investigatious of the Norwegian North-Atlantic Expedi- 
tion and the Danish Ingolf-Expedition. An account of the pheno¬ 
menon has also been worked out by Mr. A. S. Jensen (1900 & 
1902) and — as far as the Investigatious of the Norwegian 
North-Atlantic Expedition are concerned — by H. Friele (1879)^) 
and James A. Grieg & Friele (1901)^). 
It appears from the reports that shallow-water shells as Pecten 
islandicus, Portlandia arctica, Cardium groerilandicum, Astarte bo- 
realis , Venus fluctuosa , Lyonsia arenosa , Mya truncata , Lacuna 
crassior, Margarita helicina, and Trophon chathratus have been 
found at depths of 656 and 1333 fms. off Bear Island and Spitz- 
M Norges geologiske Undersøgelser Nr. 31. Kristiania 1900—1901. 
2) A. S. Jensen: I. Om Levninger af Grundtvandsdyr paa store Havdyb 
mellem Jan Mayen og Island. Vid. Medd. Naturh. For. Kjøbenhavn. 
1900. II. Fortegnelse over Skaller af bivalve Grundtvandsmollusker fra 
store Havdyb mellem Jan Mayen og Island. Vid. Medd. Naturh, Foren. 
Kjøbenhavn. 1902. 
3) H. Friele: „Catalog der auf der norwegischen Nordmeerexpedition 
bei Spitzbergen gefundenen Mollusken“. Jahrb. Deutsch. Mal. Gesellsch. 
VI. 1879. 
H. Friele & James A, Grieg: Molliisca. III. Den Norske Nord¬ 
havs Ekspedition. Zool, Christiania. 1901. 
