626 NOTICES OF THE GEOLOGY OF THE EAST COAST OF JOHORE. 
tho west coast of the Malay Peninsula. Sometimes the rock, with¬ 
out losing entirely its original structure, aspect and colour, has be¬ 
come hard and crystalline, while parts seem to be, as it were, upon 
the verge of becoming wholly quartzose. Occasionally the rock is 
entirely taicose. The blocks, from their shapes and structure, and 
the manner in which the partially altered sandstone occurs in many 
of them, have evidently been portions of highly ironmasked bands. 
Many are columnar and vesicular,—the lateral walls of the vesicles 
being in the direction of the columns and the terminal ones at right 
angles to it, as in the wood of trees. The same structure is assumed 
by the iron veins in the little altered rock. The columnar structure 
itself coincides with, and has been induced by, the direction of the 
layers of the original rock, or the laminae of deposition, as in many 
of the tubular varieties of the laterites of Malacca. Some of the 
surfaces are dull brownish and reddish brown, but in general they are 
black, highly polished, shining, and sometimes iridescent. Amongst 
the blocks were some which had a curious and beautiful appearance. 
The ordinary bright, smooth, metallic surface was interrupted, and 
succeeded by a dull fibrous structure resembling decayed wood, 
which in some places, by becoming coarser and two perpendicular 
systems of plates interlacing, changed into honeycomb. The walls 
of the vesicles or tubes, in the latter case, were composed of the 
shining ore, and the bottoms, of the unaltered or only slightly indu¬ 
rated sandstone. Larger cavities shewed sandstone in the bottom, 
intersected by numerous fine parallel iron seams. The honeycomb 
structure is therefore acquired here by the washing out of the 
sandstone between these seams. Some entire blocks had a minutely 
fibrous structure, and, if seen without the light thrown on them by the 
surrounding phenomena, must have been mistaken for pieces of fos¬ 
sil trees, until they had been broken into. In the hearts of some of 
them I found the original sandstoue isolated in patches amongst the 
iron ore. 
Here and there small masses of solid quartz occurred. 
The ore itself is internally dull, blackish, compact, with small, ir¬ 
regular, scattered vesicles. A stanhope shews quartz particles, ap¬ 
parently of the original sandstone, scattered through it, and at some 
spots regular quartz crystals and minute radiated crystals of the ore. 
Proceeding S.E. \ L., ledges of half altered grey sandstone ap¬ 
peared. These in some places were sinuous, a very common effect 
of the plutonic action to which the Peninsula has been subjected. 
