122 
Notices of Boohs. [January? 
to render direct evidence of its existence difficult to procure. 
By putting forward this view, valuable as it is to all true geolo- 
gists, the author will certainly offend that class of dogmatists 
who are now presuming to call themselves sceptics in geology. 
But we must now turn to the author’s general results as laid 
down provisionally. Till lately the most eminent naturalists, 
iudging from such limited evidence as was at their disposal, were 
of opinion that life at the bottom of the sea was confined to a 
narrow border around the land, and that at the depth of about 
ioo fathoms plants disappeared almost totally and animal life 
became scarcer and scarcer, representing only such groups as 
are among the simplest in their organisation, whilst at greater 
depths — 300 fathoms and upwards — organic life was absent, the 
physical conditions precluding the possible existence of living 
beings. Gradually, however, fadts came to light which could 
not be reconciled with this view of the distribution of organic 
life. Samples of the sea-bottom brought up from the depths of 
the Atlantic by Brookes’s sounding machine were found, on 
microscopic examination, to consist largely of the shells, entire 
or broken, of certain Foraminifera, which appeared to have lived 
where found rather than to have floated on the surface of the 
sea. Star-fishes with their stomachs full of deep-sea Foramini- 
fera were brought up from depths of 1200 fathoms. Still this 
important evidence was scarcely received as sufficient. Men of 
science hesitated to admit the possibility of animals flourishing, 
not merely in the total absence of day-light, but under a pressure 
amounting at 1000 fathoms to 1 ton on every square inch of surface. 
The results obtained by the author and Dr. Carpenter during 
their voyages in the “ Lightning” (1868) and the “ Porcupine” 
(1869 and 1870) followed up on a far wider scale by the great ex- 
pedition of the “ Challenger,” may be said to have fully decided 
this important question. 
The views formerly entertained concerning the limitations of 
oceanic vegetable life are indeed unchanged, the author finding 
that vegetation is “ practically limited to depths under 100 
fathoms.” Very few of the higher Algae inhabit the surface of 
the sea, the chief exception being the gulf-weed, Sargassum 
bacciferum. Thus marine plant life may still be regarded as 
substantially littoral. But with animals the case is totally differ- 
ent. It is present at the bottom of the sea at all depths, though 
much less abundant in the deepest parts. Still, as well-developed 
members of all the marine invertebrate classes are found at all 
depths, theirdistribution does not appear primarily connected with 
any of the conditions immediately depending upon depth. It 
appears, however, that the oceanic fauna is chiefly confined to 
two strata ; the one on and near the surface, and the other on or 
near the bottom. In the intermediate stratum the larger animal 
forms, whether vertebrate or invertebrate, are almost, if not 
entirely, wanting. The chief invertebrate marine groups, though 
1 
