100 
SKETCH OF THE PHYSICAL GEOGRAPHY 
larly over the surface of a continuous plutonic intumescence. We 
have alluded to the fact of protuberances of the plutonic nucleus ap¬ 
pearing on the outskirts of the zone, and mentioned several instances 
of their rising to a great height. But in the low undulating country 
between the great alluvial vallies, between the flat seabord and the 
mountainous interior, and between some of the mountain ranges 
themselves,—which is composed, for the most part, of ranges and sys¬ 
tems of ranges of hills, seldom rising beyond a few hundred feet in 
height, and often, in considerable tracts, not attaining the height of 
one hundred feet,—we find the hills frequently plutonic. Between 
Junk-ceylon and Pinang, granite appears frequently along the coast 
and in the islets. On the mainland opposite Pinang it rises in low hills 
at a short distance from sedimentary rocks. As we proceed south¬ 
ward we find it in the Binding islands. Of the coast from thence 
to the southern part of Salangor we have no geological account. In 
the remainder of the coast, it appears forming the anterior part of the 
hilly country extending back from the coast between Tanjong Bu- 
<Mwa and Tanjong Panehur. It rises again beyond the Town of 
Malacca in the hills of the Water Islands. At the mouth of the 
Batu Pahat or Rio Formosa plutonic hills appear. When a trans¬ 
verse section of the Peninsular zone of elevation is afforded by the 
Straits of Singapore, in a latitude where the mountains have disap¬ 
peared, we observe that from one-half to two thirds of the system of 
low hill ranges which form the island of Singapore are plutonic. 
I conceive, upon granitic bubbles" where the plutonic action has been less 
intense. The fissures and cracks formed by the pressure of these bubbles 
have been the channels, the gases given off from their surface the immediate 
agents, of all the alterations. The tracts where only granite now appears 
swelling above the surface had previously passed through the same stages. 
In other words, Iaterite is one of the earliest stages in the reduction of the 
upper rocks superincumbent on a plutonic sea into the substance of which 
that sea is composed. Where the heat has been least intense, the upper 
rocks have merely been raised,—where greater, lateritic, scoreous, and other 
partially altered, hill ranges, have been produced. A higher degre.eof plu¬ 
tonic action has produced quartzo-ferruginous ranges like that of Cape Ra- 
chado. The highest degree has transformed or reduced the whole into gra¬ 
nite and allied crystalline rocks” 
* I do not mean that each boss or hill range has a corresponding protu¬ 
berance on the surface of the plutonic base, but that the w hole system of 
hills and hillocks has been produced by inequalities in that surface, and by 
the directions which the principal and divergent lines of fracture have taken 
