GEOGRAPHICAL AND BATHYMETRICAL. 
The subjoined notes form a summary of the conditions under which the various 
soundings and dredgings which have been made use of in the present Report were 
obtained. They contain particulars as to locality, depth, and temperature, together with 
a brief indication of the physical characters of the material obtained at the several 
Stations, and of the more prominent types of microzoa observed at each. The terms 
used to describe the nature of the sea-bottom are those employed in the “ List of 
Observing Stations,” drawn up by the late Sir Wyville Thomson for the guidance of 
naturalists engaged on the various reports, in which work they are defined as follows : — 
Rock indicates hard ground, where nothing was brought up by the sounding 
instrument, there being at the same time evidence that the tube had reached the bottom. 
Mud, a material varying in colour, but derived chiefly from the disintegration of the 
land. 
Globigerina Ooze, a white or greyish deposit, formed in a great measure of the shells, 
entire or broken, of Foraminifera belonging to the genera Globigerina, Orbulina, 
Hastigerina and Pulvinulina, usually with a quantity of amorphous calcareous or earthy 
matter, and many coccoliths. 
Diatom Ooze indicates a deposit formed to a great extent of the frustules of diatoms 
which have sunk from the surface. 
Radiolarian Ooze indicates a deposit composed mainly of the skeletons of 
Polycystina and other Radiolarians. 
Red Clay indicates a deposit, very widely extended in deep water, of red, reddish, 
or grey aluminous mud, such as would be produced by the decomposition of a felspathic 
mineral. This deposit varies considerably in character ; it seems to be derived from 
several sources, but one of the most important of these appears to be the decomposition 
of pumice and other volcanic products. The “ red clay ” often contains concretionary 
nodules, consisting chiefly of the oxides of manganese and iron. 
