The Underground World: A mirror of life below the surface

by Thomas Wallace Knox

The most plausible and reasonable theory of the formation of coal seems to be that it is for the most part the remains of vegetable matter which had become decomposed and changed to mineral on the spot where it remained and is now found. The fibrous tissues of the aquatic vegetation flourished like a thick carpet on the moist surface. It became mingled and matted together, as we now find turf and peat in peat bogs, and in swamps and marshes. On the borders of great lakes, which in time were built up and became swamps, these plains extended, and underwent slow depression. Layers of sand and other substances were carried down below the level of the sea, which we now find among and alternating with the coal seams in the shape of beds of shales and sandstones. Then another system of lagoons formed above them, and allowed new jungles to spring up and new marshes to be formed. These were in turn depressed and covered by the waters. In this way, step by step, the coal beds were built up. According to geologists, each coal seam represents a depressed swamp, while the intervening strata of sandstone, and shale, and clay, mark the various sediments which were brought together by the action of the waters.

The coal beds contain many impressions of plants and portions of plants, so that geologists have been able to determine the nature of the vegetation of that period. There are a great many mosses and ferns, some of the latter having thick, broad stems, and long and heavy leaves. One geologist says there are one hundred and seventy-seven specimens of plants found in single coal beds. He says there are no palms, nor grasses, nor flowering plants; and for this reason he considers that the coal beds were formed from plants of a marshy growth.

The layers of peat, after being covered by shales, sandstone, and limestone, were compressed beneath the enormous weight of the over-lying strata, and while undergoing this compression, there was a sort of distillation and purifying process going on. In this way the plants and peat, originally loosely matted together, became more and more compressed, and by means of the heat and pressure were entirely decomposed. Ultimately the substance was turned into what we now find it, and the coal was stored up for future ages.

The ancients had curious theories in regard to the formation of coal. They regarded it as streams of bitumen, which had become petrified, or had impregnated certain very porous kinds of rock. Another theory which they entertained was, that forests had been carbonized on the spot where they grew, or had been transformed by streams of sulphurous acid, which possesses the property of hardening and carbonizing wood. It is easy to attribute the origin of coal to the agency of rivers of bitumen, and oil of vitriol; but it is not easy to say where those rivers came from.

SACRED FIRE WELLS.

The Chinese have a theory that coal is a species of plant of which the seed was deposited in the earth ages and ages ago, and that it grew and spread in different parts of the empire where it is now found, in order that the Chinese of to-day might have a sufficient supply of fuel. They attribute the streams of inflammable gas, which they collect and utilize, to the breathings of an immense monster below the surface of the earth, and in some localities they call him the first cousin of the God of Fire. The God of Fire is one of the Chinese deities. He occupies a prominent place in the temples, and is worshipped with great solemnity. In other parts of the world these streams of gas are worshipped, and in localities along the coast of the Caspian Sea, streams of burning gas are constantly rising, and their sources are known as sacred wells. They are visited by thousands of devotees every year, and are regarded with the greatest reverence.

Wells of similar character exist in the United States, but they are mostly of artificial origin. They are found in the vicinity of Oil Creek, and that region of Western Pennsylvania which has been baptized as Petrolia. Thousands of devotees have worshipped in the vicinity of these wells, and many of them owe their fortunes to the modern God of Fire; but it is doubtful if many of them worship the wells with that religious devotion and reverence which are found among the fire worshippers of the far east.

A WIRE TRAMWAY.

A novelty in the way of carrying coal may be seen at the Harewood coal mine, at Nanaimo, British Columbia. The mines are situated at a considerable elevation above the sea-level, and the intermediate ground is covered with trees and rocks, while several deep ravines intercept the grounds. Under such circumstances, the construction of a railway would be costly and require much time, as several viaducts would be required, and the road at some places would have to make considerable curves. The proprietor of the mines therefore decided to avoid all these difficulties, on putting up a wire tramway in a direct line from the mine to the port, by means of which the ravines could be spanned without expense, and the timber on the ground could be converted into the necessary posts.

There are in all ninety-seven posts, put up to such a height that the wire spanned over them forms a softly inclining plane. The distance between them is from 150 to 250 feet. The wire rope is of the best crucible steel, specially made for the purpose, and is 6-1/2 miles in length; each post having a pair of groove-pulleys two feet in diameter, over which the wire moves. The rope is driven at the lower end by an engine of 20 horse-power, which is sufficient to drive the line when carrying 12 tons per hour.