REPORT ON THE DEEP-SEA DEPOSITS. 
253 
amount of such material is annually borne to the ocean by rivers from the dry land or 
washed from the coast line into deep water. The Challenger dredgings near land 
furnished abundant proof of this in the presence of leaves, fruits, and branches of trees, 
with occasional fragments of land shells and other organic substances. Alexander 
Agassiz dredged a great abundance of decaying vegetable matter from deep water in the 
tropics, off the Pacific coast of America.^ 
h. Albuminoid and otheb, Organic Matters in Deep-Sea Deposits. 
In nearly all deep-sea deposits traces of albuminoid organic matters can be detected 
by chemical analysis. Organic material can be observed after fragments of bones or 
shells have been removed by dilute acid, when there often remain small flocculent masses 
— sometimes taking the form of the calcareous shells — which, heated on a platinum j)late, 
burn, leaving a black cinder. In shallower water, for instance in some Green Muds, there 
is a greenish matter which likewise burns and appears to be of vegetable origin. The 
presence of sulphides and sulphuretted hydrogen in all harbour muds, muddy bays near 
land, and, indeed, in nearly all the terrigenous deposits, such as the Blue Muds, is a 
sure indication that soluble and insoluble albuminoid and other organic matters are dis- 
tributed throughout these muds and are in process of decomposition. Probably sulphides 
are present in all deep-sea deposits, but they are most abundant in muds near land where 
there is rapid accumulation, and where a large quantity of organic matter is borne down 
from the continents. In the Red Clays and the other truly pelagic deposits, the quantity 
of organic matter is much less, and, owing to the slow accumulation, the sulphides are 
probably oxidised as soon as formed, and never make up any considerable portion of the 
deposit. 
The food of the deep-sea animals living on the floor of the ocean consists of the dead 
bodies of oceanic plants and animals that have fallen to the bottom from the surface 
and intermediate waters. The stomachs of Echinoderms, Annelids, and other organisms 
were always found to be completely filled with the surface layers of the ooze, mud, or 
clay of the region from which they were dredged, and there can be no doubt that the 
nutriment contained therein was sufficient for the necessities of life.^ Even the Crus- 
taceans dredged from areas where fine mud commences to settle on the bottom, about 
or beyond the 100-fathom line, appear to live largely on the minute particles of organic 
origin which there settle on the bottom along with the argillaceous matters. A very 
large proportion of marine deposits must in this way be passed through the intestines of 
marine animals, and in this sense, though not in the sense suggested by Thomson and 
^ Bull. Mus. Comp. Zodl., vol. xxi. p. 197. 
^ Murray, “ Marine Deposits of the Indian, Southern, and Antarctic Oceans,” Scot. Geogr. Mag., vol. v. p. 425, 1889. 
