GEOLOGY. 
Ill 
action of intruding granite upon sedimentary strata. In many 
places blackish schistose concretions of various forms are included 
m the granite near the lines ol contact, and exactly resembling 
the rocks ot the metamorphic strata, leading to the belief that they 
were merely fragments ot sedimentary rock embedded in the 
giamte whilst in a soft state. These rocks form, as far as Cape 
oulwmd, ^ ie wa ^ s against which the sea breaks where no sand 
beae its occur. They are bounded towards the east, as I noticed 
\v en travelling over the Tuhinu hills, by a whitish and more 
hnely grained granite, which, near the mouth of the Waitakere, 
has a gneiss-like appearance. 
. -^ or th ot the last-named stream, some magnificent cliffs are 
visible, consisting of the same micaceous schist, striking from 
n°i th-east to south-west, with a dip of 16 degrees towards the 
south-east. . Through this bed run large veins of a beautiful 
granite, ramifying in all directions, and varying in breadth from 
several feet to a few inches, and consisting of very large yellowish 
crystals of feldspar, large hexagonal tables of silvery mica, and of 
translucent quartz of a vivid bluish tint. These veins are them¬ 
selves intersected by straight dikes of greenstone, the whole 
forming the prototype of a geological section. Near Cape Foul- 
wind, the main mass of the granite is porphyritic, and on its 
western side is bounded by the same micaceous schists, here 
almost vertical, followed near the sea by semi-crystalline sand¬ 
stones. The transition from the granite to the metamorphic 
schists is sometimes almost imperceptible, it first becoming finely 
grained, and then passing by degrees into the schistose rock, so 
that it is at times difficult to find the line of demarcation. 
Near the Potikohua river, the cretaceous formation leaves the 
coast, and runs towards the Paparoha chain. Between it and the 
crystalline rocks at the coast line a large deposit of sands occur, 
partly white, partly ferruginous, finely stratified, and covering 
the sides of low granitic hills, whose tops are seen rising above it. 
In these beds, in the neighbourhood of the Waitakere, deposits 
' of lignite occur, which by former explorers have been described 
as coal seams. 
North of Cape Foulwind, and lying upon the granite rocks, the 
cretaceous formation again appears, consisting of greensand, 
stratified clays, and limestones. Amongst the uppermost visible 
strata is a limestone of whitish blue colour, consisting almost 
entirely of corals. Between the Waitakere and the Waimanga- 
roha lies the delta of the Buller, the changes in the course of the 
river as it ran through it at different periods being indicated by 
numerous terraces. 
For several miles before reaching the Buller from Omu Point, 
proofs of a gradual sinking of the surface are visible, even to the 
superficial observer. Not only have all the trees on the margin 
of the forest, which here reaches the sea coast, died, but in the 
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