1004 
the first-named contains 1.24°/, MnO,, whereas the second contains 
only a trace. This may be accounted for by the fact that no manganese 
nodules occur in the red clay of Barbados and thus the manganese 
ore there is not concentrated, as is the case in the red clay of 
Noil Tobee. For the rest the analyses 3 and 4 resemble each other 
so much, that we may speak of an almost complete identity as to 
chemical composition between the cretaceous deep-sea clay of Noil 
Tobee of Central Timor and the miocene deep-sea clay of Mt Hillaby 
in the island of Barbados. The differences between the fossil and 
the recent deep-sea clay are slightly greater. This is easy to under- 
stand, as the deposit, directly it had been raised by diastrophism 
above the sea-level, must in some measure have been modified 
through diagenetic processes, in spite of its being almost impervious 
to water. By those processes a portion of the iron has been leached 
out and removed from the rock, and silica has been introduced into it. 
Taking this into consideration the chemical composition of the red 
clay, as well of Barbados as of Central Timor, appears to resemble 
fairly well that of the recent deep-sea clay brought up at different 
stations by the Challenger, as is evidenced by the above analyses. 
The accordance in composition with the samples of red deep-sea clay 
collected by the Gazelle and analyzed by von Gümger ') is also great. 
Microscopic composition of the red clay. 
The microscopic examination of four thin slides of red clay of 
Noil Tobee, carried out by Prof. H. A. Brouwer, yielded the following 
results: ‘The major part consists of an extremely fine clay-mass, 
which cannot be determined more precisely. It contains some larger 
fragments of minerals and rocks which were recognized as 
a. a polysynthetically twinned crystal of plagioclase ; 
b. a small fragment of a voleanic rock with felsparlaths in the 
groundmass ; 
c. a strongly altered fragment of the groundmass probably of a 
volcanic rock rich in glass ; 
d. a fragment of a voleanic rock rich in glass, with felsparlaths, 
featherlets of ore and much glass ; 
e. some strongly altered (serpentinized) fragments, possibly of 
olivine originating from a volcanic rock ; 
f- an amorphous piece of quartz. 
Ill-defined remains of radiolaria, the tests of which have mostly 
disappeared, occur in a small quantity in all the slides”. 
1) W. von GiimMBEL. Ref. 5, p. 85 and 87. 
