506 
Froceedings of the Roycd Society 
3. Fine Washings. — We designate by this name the particles 
which, resting in suspension, pass with the first decantation. They 
are about 0’05 mm. or less in diameter. We have been unable to 
arrange this microscopic matter under the category of Minerals, 
for, owing to its minute and fragmentary nature, it is impossible to 
determine the species. We have always found that the Fine 
Washings increase in quantity as the deposit passes to a clay, and it 
is from this point of view that the subdivision has its raison d'etre. 
We often designate the lightest particles by the name argillaceous 
matter, but usually there are associated with this very small 
particles of indeterminable minerals and fragments of siliceous 
organisms. The number within brackets which follows the words 
Fine Washings is obtained in the same manner as those placed after 
Minerals and Siliceous Organisms. 
These few words will suffice to render the descriptions intelligible. 
Greater details will be given, as already stated, in the Challenger” 
Keport. It may be added that in the majority of cases we have 
solidified the sediments and formed them into thin slides for micro- 
scopic examination, and that at all times the examination by 
transmitted light has been carried on at the same time as the exami- 
nation by reflected light. Each description is followed by notes 
upon the dredging or sounding, upon the animals collected, and a 
discussion of the analysis whenever a complete analysis has been 
made, which is always the case with typical samples of the deposits. 
Kinds of Deposits. — We now proceed to the description of the 
various types of deposits into which it is proposed to divide the 
marine formations that are now taking j)lace in the deeper water 
of the various oceans and seas. We will speak fi.rst of those which 
are met with in the deeper water of inland seas, and around the 
coasts of continents and islands, and afterwards of those which are 
found in the abysmal regions of the great oceans. Those coast 
formations which are being laid down on . the shores, or in very 
shallow water, and which have been somewhat carefully described 
previous to the recent deep-sea explorations, are here neglected. 
A study of the collections made by the “ Challenger ” and other 
expeditions show — 
(1) That in the deejoer water around continents and islands 
