J. Murray on Sea-bottom Deposits. ee! 
far from continents and large islands, and the sediment is not 
abundant except where pumice or scoria is present. The latter, 
or slate-blue color, is found in those soundings more or less near 
continents and large islands; and it is suspected that this sedi-. 
ment has its source chiefly from the disintegration of these 
adjacent lands. 
ica, quartz, pumice, scoria, and other mineral products are 
met with; but in those soundings farthest from land a little 
piece of pumice or scoria may be the only trace of mineral 
particles, 
In some specimens there are very many remains of organisms 
d 
en entirely removed, 
and replaced by a silicate. There are reasons for thinking that 
these indications of flint (?) occur only in those samples where 
the siliceous shells of Radiolaria, Diatoms, etc., are wanting, 
those with an admixture of clayey matter we have frequently 
ne or two partial casts of a very rough character. In two 
Soundings, os. 211 and 301, in the Pacific, we found the 
Foraminifera not only filled, but also coated, with a, red sub- 
Stance, so that we had ! 
the two being connected by little rods representing the foramina 
of the shell. In these soundings there was much clayey matter 
" disi 
na f 
i; these cases the surface-layer has been normal with the 
- JOU 
