PART 3.] 
Ilochstetter, Geology of Nicotian. 
67 
At tlie time of my stay in Java (1858), and from all I could find described, as well as 
from my own observation, I came to the conclusion that in the tertiary deposits of Java two 
principal groups can be distinguished, setting aside the limestone formation, the proper place 
ol which in the system of Javanese deposits is as yet doubtful:* 1. A lower coal-bearing 
Uroup : numerous workable seams of brown coal are imbedded in quartzose non-calcareous 
sandstone and slate-clay with silieified stems of trees; marine shells are very rare, or absent. 
To this I referred the coal seams discovered by Junghuhn in the south-western part of Java, 
as also the coal formation on the Kapuas river in West Borneo, and the extensive coal 
districts in Southern and Eastern Borneo, finally tho coal of Benkulen (Bencoolen) on 
Sumatra, and numerous other similar deposits scattered over the Indian Archipelago. 2. 
upper group without coal: a, clay and sandstone formation with plastic clay-slates, 
argillaceous marls, calcareous sandstone, trachytic tufas, breccias and conglomerates, rich in 
marino shells, fossil plants, fossil resin, but merely with nests of coal in place of coal seams. 
Reasons, which 1 have given elsewhere,f have induced me to regard this complex group 
oi strata as probably of Eocene age. This opinion may even now stand as regards the lower 
group, while as regards the upper group, 1 gladly accept the opinion of my friend Baron v. 
Richthofen, and the conclusions derived by II. M. Jenkins,J from which these fossiliferous 
deposits appear to be younger Miocene. 
I suspect that to this upper Miocene group correspond the tertiary deposits of the 
Nicobars, although fossils confirming this suggestion have yet to be discovered. It is 
also beyond doubt that these deposits are not wanting on Sumatra, in certain respects a 
connecting link between Java and the Nicobars. Junghuhn (loc. cit, p. 8) justly remarks: 
“ The tertiary formation appears to have a sub-marine extent over the whole of the Indian 
Archipelago, because wherever within this Archipelago the earth’s surface rises above the 
level ol the sea, this ueptunian formation is observable. I know this for certain as regards 
Northern Sumatra, where the tortiarios are especially found in the Batta districts (Batta 
landern). With the exception of the trachytic island Oungus Nasi all the islands in the" 
Bay,of Tapannli (situated exactly in the prolongation of the Nicobars), besides tho 
adjoining low shores of Sumatra, and partially also the mountains near Tuka, are composed 
ol more or loss upheaved sandstone strata, containing, though sometimes rarely, tertiary 
shells. ’ Thus it appears to be principally on the southern coast of Java and tho south-west 
coast of Sumatra that we find a repetition of tho geological conditions of the Nicobars. 
The commencement of tho eruptive formation is in Java inaugurated by Serpentine, gabbro > 
massive rocks resembling diorito (greenstone trachytes as in Hungary); more or less typical 
trachytic rocks follow, and the grand volcanic eruption extending up to the present time 
irom the termination of the enormous eruptive phenomena in the Indian Archipelago. 
At the same time it appears that the eruptive line has been shifted slowly, on Java from 
south to north, and on Sumatra from south-west to north-east, so that this line would 
strike east as regards the Nicobar group in the same longitude in which oast of the 
Andamans it reappears on the Volcanic Barren Island and Nareondam. 
The young tertiary ago of tho serpentine and gabbro eruptions on the Nicobars and 
Java has its perfect analogue in tho eruptions of the same rocks in Central Italy, which, 
according to Signor Perazzi, in Turin, and Prof. Savi, are partly Eocene, partly Miocene, and 
which, on account of their copper ores, are of importance to the miner. 
The third principal formation of the Nicobars are coral formations, belonging to the 
most recent or the present period. Coral banks of great thickness are found onCar-Nicobar, 
Bompoka and several other islands; they consist partly of a compact coral limestone, partly 
of a coral or shell conglomerate, upheaved up to 30 and 40 feet above the present level of 
the sea; on all the islands, the original area is to be observed enlarged by coral-land, which 
is only separated by the higher sand dunes along the shore, from tho still continuing form¬ 
ation ol tho coral reefs surrounding all the islands in tho character of fringing reels. 
Although these raised eoraj banks are a decided evidence, in favor of the long continued 
* According 1 to Junghuhn this limestone is the youngest of all the formations, and is always to be found only in 
superficial banks. ^ 
t Reports on the doings of the mining engineers in Netherlands India (Jahrbuch der k. k. geol. Reichsanstalt. 
Wien, 1858, p. 277). 
t Quart. Jour. Geol, Soc,, London, Feb„ 1864,—F, Baron v, Richthofen, Zeitschrift der deutschen geol, Gesell* 
schaft. Bd. 14, p, 327, 
