A general account of the Geology of the Malay 
Peninsula and the surrounding countries, 
including Burma, the Shan States, Yun- 
nan, Indo-China, Siam, Sumatra, 
Java, Borneo and other Islands 
of the Dutch East Indies. 
BY 
E. S. WILLBourn, 
Assistant Geologist, Federated Malay States. 
Introduction. 
This account is a digest of the writings of many geologists. 
It would occupy too much space for me to detail all of them, but 
most of my information was derived from the following:— La 
Touche on the Northern Shan States, Middlemiss on the ‘Southern 
Shan States and Karenni, Coggin Brown on Burma and Yunnan, 
Résultats de la mission géologique et miniere du Yunnan méri- 
dional, Sept. 1903—Jan. 1904, Situation de l’Indo-Chine de 1902- 
1907, Scrivenor on the Malay Peninsula, Molengraaf on Borneo, 
Van Cappelle on the West Coast of Sumatra, Wing Easton on West 
Borneo, Verbeek on the Moluccas, Amboyna, Banka, and Billiton, 
and various authors in the Jaarboek van het Mijnwezen in Neder- 
landsch Oost-Indve. 
The area dealt with meludes Burma, the Shan States, Yunnan, 
Siam, Indo-China, the Malay Peninsula, Sumatra, Java, Borneo, 
and the intermediate islands. Unfortunately, the most satisfactory 
method of presenting a general idea of the geology, namely to 
prepare a geological map and to base the discussion on it, is not 
available, because the geological structure of most of the countries 
has not been mapped. In spite of this, enough is known, even in 
the least known regions, such as Yunnan, and parts of Indo- 
China, to compare the rock formations of any. particular period 
in the different countries, and from the present features it is 
possible to trace the effects of certain wide-spread earth-movements 
which have affected all the countries in the area, and to compare 
them with the effects on neighbouring lands. 
Large gaps occur in our knowledge of the area, so blanks 
must exist in our comparison of the structure of the different 
countries. It must be admitted, however, that these gaps are 
not alwavs the result of imperfect knowledge of the countries 
in question, for, in more than one case, geologists are at a loss 
to account for phenomena in countries where the structure is 
wour. Straits Branch R. A. Soc., No. 86 1922. 
