GEOLOGY. 
105 
. ^e seams F and H, striking north and south on the western 
side, and with a dip towards the west of 11 degrees, are again 
visible on the eastern side of the chain, where they have the same 
strike, but there they dip 13 degrees towards the east. As we 
near the axis ol the chain the dip becomes greater, and increases 
at the lowest visible seam from 9 degrees to 26 degrees. The 
main seam contains a magnificent and very compact coal, and 
evidently has not been so much disturbed as the seams M, O, and 
Q, which we meet with in the centre of the section, the last three 
striking east and w'est, with a dip towards the south of 26 de¬ 
grees. The seams INI and 0 have been cut through by the river 
transversely to the flexure (or bend), and their upper parts only, 
lying sixty feet above the river, are occasionally exposed, the re¬ 
mainder having been washed down, partly by rivulets flowing 
from the mountain, and partly by the main river during freshes. 
Amongst the detritus which here covers the sides of the moun¬ 
tains, and which is in fact only the remains of large slips, the seam 
Q is visible. It is very much cracked, the coal fractured and 
brittle, and at the same time lighter and more bituminous than 
that of seam H. 
The coal-field, although of a more recent formation, presents 
exactly the same characters as those belonging to the true car¬ 
boniferous period; we meet with the same shales, grits, and sand¬ 
stones, and the coal itself cannot be distinguished from deposits 
of primary age. The larger seams have their under clays. The 
grits consist of quartz grains, very little rounded, with occasional 
crystals, and of mica and feldspar, the whole embedded in a com¬ 
pact silicious matrix, so that, although of pure mechanical origin, 
they resemble a coarse granite (arkose). In some places the mica 
predominates, lying in thin horizontal bands in a silicious matter, 
frequently coloured by carbon, together forming a beautiful rock, 
the contrast of the black matrix with the silvery mica being very 
striking. There are also some bands of pure mica, three to four 
inches think, which by pressure have been formed into a rock, so 
closely resembling a real mica slate, that it would almost be im¬ 
possible to detect any distinction between them, unless its origin 
were known. How various and sudden must have been the 
alterations in the conditions of the currents of the sea, and in the 
level of the land, to allow of the deposition of such different strata 
often within a single inch of each other. The coal itself cannot 
be distinguished from the Newcastle coal of Australia, its struc¬ 
ture, lustre, specific gravity, mineral composition, and combusti¬ 
bility being similar. 
I may here give an analysis made by Mr. Tatton, of Nelson, 
which confirms me in the belief, originally formed on the spot, 
that this coal-field is of the same age as that of Newcastle, 
namely, the great oolite. 
