studded with the shells of molluscs which lived and enjoyed existence when this limestone was the ocean's bed, and the light of day shone down upon their quiet abodes as it now shines upon the busy builders of the coral reef. The light of day!—but a day of God's eternity, which dawned upon our planet before Elohim had said, "Let us make man in our image." Rapidly through the belt of limestone our little car descends, and we next find ourselves environed by a wall of sandstone. Here and there are streaks and patches of dark carbonaceous material, and occasionally the eye catches glimpses of woody stems imbedded in the solid rock. But hark! a sound of water rises from the darkness beneath. A subterranean stream has been intercepted, and a little rill is trickling down the massive wall-side. Again in the midst of black, bituminous shales; and now we hang suspended opposite an opening in the stony wall. One hundred feet above our heads the light of heaven is still visible, and three hundred feet below are darkness and emptiness. On the right and the left are entrances to chambers which have been excavated in a seam of coal occurring at this level. But the end of our journey is not here. Continuing to descend, we perceive the bed of coal underlaid by clay, with abundant grass-like shoots and occasional stems of vegetation. In turn we pass shales and sandstones, and then seams of coal, till, at the depth of two hundred feet beneath the surface, we hang before another portal to a long, dark avenue excavated in a deeper-seated bed of coal. In some of the dark and dusty chambers of the labyrinth which opens here the miner's pick is heard resounding, and now and then the muffled report of the miner's blast comes echoing through the vaulted aisles. But this is not the station where we intended to stop. on, and we plunge through two hundred feet more of the

Our car moves

rocky rind of the earth. Above us, the mouth of the shaft seems narrowed by perspective into an insignificant hole; before us opens a dark street, over which, on a tramway, mules are hauling car-loads of coal, which is starting on its journey to the populous city (Fig. 61). Miners, with their picks, are moving to and fro; the sound of hammers is heard; the paraphernalia of busy life are about us, and we seem translated to a nether world. We feel like the hero of the Latin song, who got permission to visit the realm. of Pluto, and make the acquaintance of unborn spirits destined to dawn upon the world in the coming Golden Age. Where is the Styx and its sleepy boatman? Where are the shades that expectation thinks to see flitting before us? Let us enter this dingy street, and conjure spirits from their Lethean sleep upon the coaly couches that line the passage-way.

The seam of coal is a broad, horizontal sheet or bed from three to five feet thick. In this are excavated passages about eight feet wide and about five feet high. A main "gangway" may be half a mile or a mile in length. From this, at suitable intervals, lateral passages or "chambers" are quarried out, running nearly at right angles with the main gangway. The same bed of coal may be pierced by several gangways-diverging from each other as the ave nues diverge from the Capitol at Washington-from each of which extend numerous lateral chambers. These chambers often intersect each other, and thus constitute a network of passages like the streets of a city. Along the principal passages tramrails are laid for the transportation of the coal in trams, or little cars, from the remote portions of the mine to the shaft. Each miner employs a separate tram, and receives a stipulated amount per ton for the coal sent up by him. The trams are moved over the track by mules, which often spend their lives under ground. They