112 
GEOLOGY. 
tide-way itself, and even for three feet below high-water mark, 
we find the whole line a succession of huge dead trees, still rooted 
to the bottom, and presenting with their naked branches an image 
of utter destruction. It is impossible that they could have stood 
for any great length of time in such a position without having 
been uprooted, many of them in fact being already prostrated on 
the sand ; and we may therefore infer that as some spots on the 
eastern side of this island have been raised several feet during the 
last few years by earthquakes, doubtless proceeding from sub¬ 
marine volcanic eruptions, so on the western side sudden de¬ 
pressions have occurred so as to submerge those forests. 
It would lead me too far were I here to cite all the difterent 
data I possess concerning volcanic action and earthquakes, and 
the consequent change in the level of these islands, and 1 must 
therefore keep them for future publication ; but I may add, that 
although everything I observed proves that whilst the eastern 
side of the island rises, the western falls, there have been occa¬ 
sional oscillations, as observable, for instance, between the Rivers 
Wanganui and Karamea. Here we find sand beds twelve feet 
high, with small layers of magnetic iron-sand between, upon which 
the sea is now continually encroaching. That these Banks are 
not formed of drift sand is not only shown by ripple marks, and 
by the presence of numerous shells similar to those now existing 
on the sea beach, amongst which Venus intermedia in perfect 
condition is most frequent, but also by that of a large drift tree, 
now rotten, which lay amongst these beds. From these facts we 
may conclude that but a few years have elapsed since they were 
upraised. 
In ascending the Buller, we observe, before reaching the gorge 
where the river enters the mountains, a succession of apparently 
young strata, a blue clay marl overlaid by a soft ferruginous sand¬ 
stone. At the western foot of the chain, north of the Buller, the 
same formation also occurs ; but here, between the blue clay 
marls and the sandstone, lie about twenty feet in thickness of 
black marls with mica scales. The general strike of these beds, 
which are 250 feet above the level of the sea, is from north-north¬ 
east to south-south-west, with a dip towards the west-north-west 
of 17 degrees. Above them the alluvial deposits begin. The 
gorge itself exhibits a syenitic granite of an even structure for 
several miles, through which the porphyritic granite is protruding 
in large veins. Greenstone dikes occur also in some spots. 
This granite extends north of the Buller in a wedge-like form 
into the Papahaua chain, forming hills of 500 to 1,000 feet high, 
and ceasing in the centre of the' chain. On both its sides, uniting 
in the centre, lie the coal-bearing strata, striking, at Mount 
Bochfort, regularly east and west, with a dip of 5 degrees towards 
the north. These strata, although of the same age as the Grey 
coal-fields, and consisting of the same gritty and shaly beds, 
