90 
THE GEOLOGY OE NELSON. 
mineral is an ordinary accompaniment of serpentine rock, and 
occurs in the Dun Mountain in great force. Of its commercial 
value I do not feel myself qualified to speak, but should its 
value be considerable, the abundance of it is so great that it 
must prove a source of much wealth to the mine. 
Having described the central parts of the western ranges, 
and the serpentine which Hanks it, there still remains to me to 
describe a zone of old sedimentary rock, which lies between the 
serpentine on the east, and Blind Bay and the Waimea plain on 
the west. The best section of this zone is obtained by following 
up the course of the Maitai to the Duu Mountain. Imme¬ 
diately to the west of the serpentine we meet with a belt of 
calcareous schists, which attains its highest elevation on the 
summit known as the Wooded Peak, and continues on its 
strike parallel with the serpentine dyke. Proceeding to the 
westward, we pass over a band of greenish and reddish coloured 
slates, of a thickness of about five English miles. The same 
description of slates continues all along the ranges, as far as 
the Big Bush road to the Wairau. The absence of any fossil 
remains in the calcareous schists and in the slates prevents 
me from assigning to them with confidence their geological 
age. I give them therefore a local name, and call them the 
Grreen and Red Maitai Slates. In places these slates are broken 
through and altered by eruptive rocks, as, for instance, in 
Brook Street valley by diabase, and near Wakapuaka by 
sienite. 
(3.) Secondary Formations. 
Between Nelson and Wakapuaka, black slates and shales 
are found close to the edge of the water. In these we find the 
first indications of organic remains. Of the nature of these 
organic remains I have not been able perfectly to satisfy 
myself; they appear, however, to belong to the vegetable 
kingdom, and have more resemblance to sea-weeds than any¬ 
thing else. 
In the same line, further south, the Richmond sandstones 
form the boundary of the western ranges. No less interest 
attaches to these sandstones, which contain many and perfect 
fossil molluscs, and are, so far as I know, the oldest fossiliferous 
strata in the Province. The fossils belong to the genera 
Mytilus, Monotis, Avicula, Spirifer, Terebratula, which seem 
