1514 
In connection with the presupposed precarbonic age of all granites, 
the occurrence, in the Highlands of Padang, of rocks with contact- 
minerals (crystalline limestones with garnet and vesuviane-garnet- 
rocks, silicified marly claystones, a. o.), which often occur in immediate 
contact with granites, has been explained as a consequence of the 
intrusion of younger basic rocks (diabases, gabbro); and solutions 
that at the same time caused the formation of different ores, were 
supposed to have circulated at the very contact of the granite with 
the adjacent rocks. 
In the following pages examples will be cited, from which it is 
evident that the metamorphism at the contact of granites and carbo- 
niferous — partly perhaps younger — sediments, agrees with that which 
is always considered as a proof for the younger age of the granites. 
The very interesting mineralogical characteristics of this contact- 
metamorphism will form the subject of a paper dealing more parti- 
cularly with the matter, only the chief characteristics being mentioned 
here. I shall treat subsequently: a granite-limestone-contact to the 
West of Kota Tua on the northern foot of the volcano Singgalan, 
a granite contact near Pamusian on the Sinamar, already mentioned 
by Verbeek, and the contacts of the Siboumboun mountains (to the 
East of the Lake of Singkarah’), equally mentioned by VeERBEEK. 
Contact to the West of Kota Tua. 
On the left wall of the river Sianog, before the mouth of the 
Set Limau originating on the voleano Singgalan, and close N.N.E. 
of the bridge along the road to Matour over the latter river, I found 
in a landslip a contact of granite and limestone strongly meta- 
morphosed at the contact (fig. 1). As a matter of course, in con- 
tg 
(a ke vk 
: 2 My 
Fig. 1. Contact between granite and limestone, exposed in a landslip to 
the W. of Kota Tua (& = contactmetamorphic limestone, garnet-rock ete.). 
1) R. D. M. Verseex. Topographische en Geologische Beschrijving van een 
Gedeelte van Sumatra's Westkust. Batavia 1883. p. 160, 242, 250, 254 etc. 
