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The gaseous mixture contains, in each 100 volumes —
Other inflammable gas - - 52
- 14:35 Oxygen
- 600 Geological Situation. — It lies among clays, in beds of two feet thick, in which no impressions of plants are perceivable, nor is any sandstone visible; and the want of a natural section precludes a more accurate detail: the two shafts, sunk to the depth of 150 feet below the crop of the seam, discover nothing but horneblende, dolerite, and steatitic rocks, with sulphate and carbonate of lime.
SLATE Coal. (Jameson.)
Colour, black; structure slaty, the layers dividing into brittle fragments of indeterminate angular shape; fracture even, lustre resinous and shining; specific gravity, 1.33.
Chemical Character. - It burns with a splendid white and reddish flame, and is easily lighted; emits black smoke, and swells and agglutinates: its proximate elements are
The Upper Seam. | The Lower Seam, at 32 fl. deeper. Charcoal - 64.0 Charcoal
• 32.0 Bitumen Earthy matter - . 40 Carbonate of lime - 5700
| Silica The coal of the upper seam gives two cubic feet of illuminating gas for every pound consumed. It moreover gives, in every 100 parts of weight
Coal-tar and ammoniacal liquor 12:6
Coke · · · · · 77.0
- 64 Its ultimate elements, deducting the earthy matter, will stand in the following proportion:The Upper Seam.
The Lower Seam. Carbon .. 72-2 | Carbon
52.3 Hydrogen - - 14.4 Hydrogen - - 17.2 Oxygen
4.6 Oxygen Nitrogen 868 | Nitrogen
Chemical Character. - Burns with a splendid white flame, and is easily lit : its proximate constituents are
- - . . 37
One pound gives two cubit feet of an illuminating gas, like that obtained from the Jerusalem coal: the quantity of coal-tar is also the same, but there is less coke.
Its ultimate elements, deducting the earthy matter, are as follows:Carbon.
- - - - 74:3 Hydrogen
- 10:4 Oxygen
- 4.2 Nitrogen
- - - 10:1 Geological Situation. - From the examination of the place where it is found, and of the intervening country between the Coal River and Jericho, this deposit appears to be a continuation of that of Jerusalem. Its external and chemical character, as well as geological situation, identify the seam with the upper one of the latter locality.
Earthy LIGNITE. Loc. — Nine Mile Marsh, Jerusalem Basin, V.D. L.
Colour, black; structure slaty, resembling coal; friable; soiling the fingers; specific gravity, 1:40.
Chemical Character.-Burns without flame or smoke; when exposed to strong heat, does not melt nor agglu. tinate: its proximate constituents are
Charcoal - - - - - 40
Eartý impurities : : Geological Situation. It lies in small beds, amongst greywacke and greenstones.
LIMESTONE Rock. The yellow limestone with Bulinus and Helix, and some impressions of leaves of an extinct vegetation, ular fragments pe, showing
and which was noticed at Hobart Town, as the next to the sandstone, which forms the highest beds in geological series of the two colonies, presents mineralogically four varieties.
First Variety. — Its colour is yellow; its structure rather peculiar; without the assistance of a glass, appearing to be very fine-grained homogeneous mass ; but when viewed through the microscope, showing an aggregate of angular fragments of a brownish yellow limestone. The structure of the fragments, as well as of the paste, is not discernible. The fracture is even and dull, but the glass discovers in the paste a splintery appearance. It does not adhere to the tongue, but exhales an argillaceous odour when moistened.
Second Variety. — Structure cellular, and in crusts, having delicate undulated seams, and each bounded by its own surface; fracture splintery, the fragments angular.
Third Variety. — Colour, brownish yellow; consists of distinct concretions, which are sometimes very fine, and only distinguishable by their glimmering lustre; sometimes coarse and granular; the fracture is uneven and shining, the fragments angular, the external and internal aspect similar; it does not adhere to the tongue, neither does it yield an argillaceous odour.
Fourth Variety. — Is of a light straw colour; structure massive, slightly perforated, and composed of minute concretions; fracture uneven, the fragments angular; the external and internal aspect dull and earthy; it adheres to the tongue, yields an argil. laceous odour, and is moderately tough.
General Remarks upon the Third Epoch.
Associated with the above-described mineral deposits, in the Newcastle, South Esk, and Jerusalem basins, are found greenstone, basalt, and trachytic conglomerates, the eruption of which, as attested by the effects it produced amongst the stratified masses, took place at four different periods.
The first period of eruption is coeval with the deposition of the coal in Jerusalem basin; that is, it came after the deposition of the second seam of coal, and before that of the superincumbent clays; the said seam consisting of altered coal, from which the bitumen has been in a great part expelled, and its place supplied by carbonate of lime. (Vide the Chemical Analysis of the Jerusalem Coal.) The clays which lie above this seam are somewhat unconformable to it.
After this came the irruption of basalt and greenstone, which must have taken place between the deposition of coal and that of the variegated sandstone. Thus at Research Bay and South Port the coal is mostly charred and converted into coke from the immediate contact with the greenstone, while the variegated sandstone is left undisturbed.
The third and last period of irruption may be traced to the closing of this epoch. Besides other effects, which will be noticed in the following pages, it caused great dislocation, amidst both the coal beds and the superincumbent sandstones. At Mount Wingen, it raised the lower arenaceous rock, containing spiriferæ and conulariæ, from beneath the coal deposits which it threw out. In the Newcastle cliff, as represented in the section, it produced seven different dislocations through the irrupted greenstone which is seen under that cliff. At Port Arthur coal-pit, innumerable faults are also observable; and