CHAPTER II. 
ON THE NATURE AND COMPOSITION OF THE SPECIMENS OF DEEP-SEA 
DEPOSITS COLLECTED DURING THE CHALLENGER EXPEDITION, AND 
THEIR VARIATIONS WITH CHANGE OF CONDITIONS. 
In this chapter each specimen of marine deposit collected during the Challenger 
Expedition is described with considerable detail in a series of Synoptical Tables, and 
these Tables are follo'wed by observations indicating the more striking variations which 
these deposits undergo with a change in the depth, in latitude, in the temperature of the 
surface waters, and in the distance from continental and other lands. 
a. Synoptical Tables. 
In Chapter L the methods followed in the macroscopic and microscopic examination, 
as well as in the chemical analyses of the de] 30 sits, have been pointed out. The results 
obtained by the application of these methods to the study of the Challenger collections 
are set forth in the following Synoptical Tables, which form a methodical repertory of 
the facts observed at each of the Challenger’s sounding and dredging stations in so far 
as these refer to the deposits now in process of formation. The descriptions follow the 
order in which the specimens were collected during the voyage. The specimens have all 
been treated in a uniform manner, and it is believed that these Tables contain all essen- 
tial details regarding the characteristic properties of each specimen of the deposits. The 
numbers of the stations correspond to those on the charts and diagrams at the end of the 
volume, in which the temperature conditions and the geographical and bathymetrical 
distribution of the deposits are represented. The reader is referred to the previous 
chapter for a definition of all the terms and headings made use of in the tables.^ 
The facts summarised in these Tables serve as a foundation for the descriptions in 
Chapter IIL, where each type of Deep-Sea Deposit is considered in its ensemble, and for 
the conclusions in subsequent chapters where the origin of the materials which make up 
these deposits is discussed. In addition, however, to the Challenger collections, a very 
large number of samples from other expeditions and from many other regions of the 
ocean, have been examined in a similar manner, and have likewise served as a foundation 
for all general conclusions. 
(deep-sea deposits chall. exp. — 1890 .)- 
1 See page 26. 
5 
