THE GEOLOGY OF THE MALAY PENINSULA. 249 
underlying the Carboniferous or Permo-Carboniferous limestone 
‘of the Langkawi Islands. 
In the Dutch East Indies the pre-Cretaceous beds younger 
than the Permo-Carboniferous limestone are thought to be represent- 
ed by the “old schist formation.” already mentioned in the aan 
tion of the pre-Cambrian rocks. As stated in that description, 
many authors have relegate] it, largely on the ground of the lack 
of fossils, to the pre-Cambrian, and others to the Palaeozoic period, 
but it bears a strong resemblance to the altered shales and guarbs 
ites of the Malay Peninsula, and it was probably deposited at the 
same time. If this is so, the radiolarian chert beds and the Rhaetic 
of the Archvpelago are part of the “old schist formation,” or the 
“Malayan Series” as it was called by Volz. 
In Sarawak a limestone containing middle Oolite fossils is 
known 
In the Northern Shan States of Burma, the Napeng beds of 
Rhaetic age pass conformably into the succeeding Namyau series, 
which consists of basal conglomerates, overlain by sandstones, shales, 
and clays, with very subordinate carbonaceous layers. In the 
greater part of the north of our area, continental conditions were 
prevailing (as in the Rhaetic period), and the old land surface to 
the northeast was gradually rising, with a consequent advance 
‘southwards of the shore line, so that the sandy sediment from it 
was deposited as the Namyau series. This series of beds once 
‘covered a wide area, but denudation has entirely removed it from 
the western portion of the Shan Plateau, and the portions still 
remaining only owe their preservation to the fact that they were 
faulted down, and so protected from the severe erosion in post- 
Jurassic times. The rocks are thrown into regular folds striking 
irom NEN EH. -to S.S: W. 
Cretaceous. 
It was probably during the Cretaceous period that the granite 
which runs from the Southern Shan States, through Tavoy and 
Meregui to the Malay States, to Singapore, and the islands of Banka 
and Billiton, was intruded, bringing with it tin and tungsten mine- 
rals. Dutch authors think that the granites and hornblende- 
granites of the Archipelago were intruded at different periods, 2nd 
the granite of Amboyna is held to be older than the Permion. Ti 
may be of the same age as the granite from which the frag- 
ments in the Pahang Volcanic series ash of Singapore were derived. 
Granitic rocks in Eastern Yunnan contain cassiterite, and 
_the tin deposits of Ko-chin have been derived from them. ‘T'wo 
French geologists agree in assigning to them a Palaeozoic age, 
and, if they are right, this is very interesting, as showing that the 
tin deposits of the area which we are considering were not all 
brought by granite of one period. Many of the coulisses, mentioned 
in the earlier part of this account, came into being as a result of the 
intrusion of the Mesozoic granite. 
eA SOG. NOL So) LO22. 
