408 
of by the mixed. character of the deposit, some of the shells being 
unsuitable for such a purpose'. 
It can not. precisely be deduced, neither from W. Spotswood 
Green's narrative of the cruise nor from Nicholl's report on the 
molluses from the Expedition, how many dead shells occurred on 
the Rockall-banks, but below is named all the dead shells occur- 
ring during the whole Expedition together with Nicholl's remarks 
about them: — 
Anomia patelliformis, Linné. 100 fathoms. 2 
Pecten islandicus, Miller. 100 fathoms. Two valves, probably 
semifossil, one of which, however, has a 
recent appearance. 
Pecten tigrinus, Miller. 100. fathoms. Two valves. 
Lima loscombii, G. B. Sowerby. 100 fathoms. One valve and 
portions of two others. 
Mytilus modiolus, Linné. 100 fathoms. Dead valves. 
Cardium echinatum, Linné. One valve. 
ÅAstarte sulcata, da Costa. 190 fathoms. Dead valves. 
Dosinia lincta, Pultenay. 100 fathoms. Single valves. 
Venus casina, Linné. 100 fathoms. Three left valves, dead. 
Venus fasciata, da Costa. 100 fathoms. One valve. i 
Mactra solida, Linné, var. elliptica. 100 fathoms. Single valve. 
Thracia papyracea, Poli, var. villosiuscula.. 100 fathoms. 
Portion of right valve. 
Mya truncata, Linné. 100 fathoms. Portion af valves, dead. 
Saæicava rugosa, Linné, var. arctica. One specimen, with the 
two valves united, and single valves. 
Trochus millegranus, Philippi, 120 fathoms. A dead specimen. 
Buccinum undatum, Linné. 100 fathoms. A broken shell. 
Buccinopsis dalei, J. Sowerby. 120 fathoms. Two dead shells. 
It is much to be regretted that Mr. Spotswood Green, im 
making the occurrence of these slells the foundation of a sinking 
hypothesis, has not at the same time tried to determine the vertical 
