399 
not in the least improbable that tbe ice in melting may have 
deposited so many shells that a few specimens, in certain places> 
can be brought up almost in every dredging. 
To point 3) must be observed that it is not necessary that 
the floating ice should damage the shells which it carries away. 
Several of the molluscs, found ou the ice in the North Polar Basin, 
were whole specimens, and I do not doubt that Prof. Fr. Nansen 
is right when he sets off as his opinion that shells which are 
frozen up between ice-tlakes, among gravel and clay, may be trans¬ 
ported long ways fairly whole and undamaged. 
As to point 4) it is certainly incorrect to state that dead 
shallow-water shells do not occur at considerable depths south of 
the submarine ridges between Færoe—Iceland, Iceland—Greenland, 
and in the Davis Strait. Such shells have really been found. 
Jeffreys^) records thus from the Davis Strait and south of Green¬ 
land Astarte horealis from a depth of 1450 fathoms, and fragments 
of Mya truncata from 175 fathoms. For the first named form it is 
about 1300 —1400 fms., for the last named about 100 fms. 
below the level, where they are known to live in the North- 
Atlantic. In the same manner Jeffreys mentions^), from a depth 
of 1450 fms., fragments of Diplodonta torelli Jeffr. which, according 
to F r i e 1 e ’ s opinion , does not live at approximatively so great 
depths. Moreover it must be added thatPosselt (1.c. 1898) in his 
statements of the vertical range of the molluscs at the coasts of 
Greenland as a rule does not mention whether the found specimens 
were alive or dead, and that in all probability many of his state- 
Pr. Nansen: Letter to Brøgger in „Nivåforandringer“ etc. p. 94—9(5. 
*) J. Gw. Jeffreys: „The Post-tertiary Fossils procured in the late 
Arctic Expedition“ etc. Ann. & Mag. Nat. Hist. IV. Ser. vol. 20. 
J. Gw. Jeffreys: New and peculiar Mollusca procured in the „Valo- 
rous‘‘ Expedition. Ann. & Mag. Nat. Hist. IV. Ser. vol. 18. 
H. Friele: „Catalog der auf der norwegischen Nordmeerexpedition 
bei Spitzbergen gefundenen Mollusken“. Jahrb. Deutsch. Mal. Gesell. 
Jahrg. VI. 1879. 
