Geology. — “On Manganese Nodules in Mesozoic Deep-sea deposits 
of Dutch Timor’. By Prof. G. A. F. Moneneraarr, with a 
preliminary communication on “fossils of Cretaceous Age in 
those Deposits’. By Dr. L. F. pr Braurort. 
(Communicated at the meeting of November 27, 1920). 
Deep-sea deposits, which resemble in nearly every respect the 
recent deep-sea oozes have in tie latter three decades been observed ') 
in many islands of the Kast-Indian Archipelago’), notably in the 
islands Borneo, Rotti, and Timor. In Borneo they are of mesozoic, 
probably of pre-cretaceous age, in Rotti partly of jurassic, and in 
Timor, as had been accepted until now of triassie and of jurassic 
age. Red clay-shale here and there containing radiolaria, being the 
equivalent of the recent red clay, as well as chert and hornstone 
with radiolaria, so-called radiolarites, being the equivalent of the 
recent radiolaria-ooze, have been found and take up a foremost 
place among the rocks composing the soil of these islands. Manga- 
nese nodules are not wanting in the mesozoic deep-sea deposits and 
I have succeeded in proving®) that they enclose numerous radiolaria, 
and thus have been formed by the precipitation of manganese in 
an ooze containing radiolaria. The nodules of manganese, which 
had been found prior to those described in this paper, differ from 
those of the recent deep-sea deposits in two respects. They do not 
present, at least not distinctly, a concentric structure, and they 
do not include other fossils besides radiolaria. Recent manganese 
nodules from the deep-sea, on the contrary, have as a rule a con- 
centric arrangement and not seldom the nuclei around which they 
are grown, consist of fossil remains, as e.g. teeth of sharks. Shark’s 
teeth devoid of any coating of manganese were frequently brought 
up in great quantities by the Challenger-expedition from great depths 
in the red clay, showing that in such cases these teeth were lying 
loose on the bottom of the sea. 
1) They are deposited in the deepest parts of the mesozoic Tethys-geosyn- 
cline and considering their character of deep-sea deposits, comparatively 
close to the land. 
*) See References 1, 2, 7, 8, 9, 10, 11, 12. 
8) G. A. F. MOLENGRAAFF, Ref. 9, pp. 426 and 427. 
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Proceedings Royal Acad. Amsterdam. Vol. XXIII. 
