it passed under the limestone rock-a belief which had taken the form of the dictum "No coal under the Magnesian Limestone."

In remarkable contrast to this were the views of Dr. William Smith, who for many years had been industriously engaged in mapping out the surface rocks in various parts of the kingdom, and tracing their relative positions-in fact working out the great idea he had conceived that the rocky strata preserved an unvarying order like the leaves of a book; and that though some were occasionally wanting, none were ever found out of their true place in the series. This was only rendered possible by means of the important discovery he had made that each rock formation contained organic remains peculiar to the era in which it had been deposited, which gave an infallible clue to the identification of the strata belonging to it wherever found. Smith was thus laying the foundation of the modern science of geology.

In the course of his practice as an engineer and mineral surveyor, Smith accidentally met with Colonel Braddyll, in London, which led to his being employed by that gentleman, in 1821-2, to make a survey of some estates belonging to him in Lancashire, Cumberland, and Durham. The interest which Smith felt in the properties in the two former counties was altogether inferior to that with which he scrutinised the estate in Durham. This included the village of Haswell, and

comprised seven hundred acres of poor land, situated on the Magnesian Limestone, and regarded as of little value by Colonel Braddyll's agents. The proprietors of adjoining estates shared the same opinion, few of them believing that their properties had any other than surface value. Smith, however, at once saw that the limestone was an unconformable cover to the coalmeasures; and having traced the course of these, and estimated the thickness of the limestone, he inferred that the best seams of coal would be found at an attainable depth at Haswell.

No immediate steps were taken to open out the coal in Colonel Braddyll's property, but within a few years sinkings through the limestone were effected elsewhere, and the correctness of Smith's inductions abundantly verified; and this extensive area, hitherto regarded as of no value, became the scene of the winning of some of the largest, deepest, and most costly collieries that had yet been opened out.

The work of piercing through the limestone, to the coal-measures beneath, was in some cases attended with extraordinary difficulty and cost. This was partly occasioned by the open character of the rock itself, which, being intersected by numerous large fissures, discharged vast quantities of water into the shafts; but a still more formidable difficulty presented itself in most cases when the bottom of the limestone was reached. Here, at the break between the two

unconformable formations, a bed of loose sand existed, of varying consistency and thickness, but always yielding great feeders of water, to penetrate through which was at times a task of immensely greater difficulty than cutting the hardest rock.

Foremost among the deep sinkings made through the Magnesian Limestone, alike in point of time, depth, and boldness of conception, was the famous pit put down by the Messrs. Pemberton at Monkwearmouth Sinking was commenced in May, 1826, and notwithstanding great difficulty and discouragement, the works were pushed forward in a spirited and determined manner. The progress, however, was slow, and it was not till August, 1831, that the first unequivocal stratum of the coal formation was reached. This consisted of a seam of coal one and a half inches in thickness, found at the depth of 344 feet from the surface. The thickness of the covering of limestone was 325 feet, and the stratum of sand, at the breach between the Permian formation and the coal-measures, was five feet thick. At the bottom of the limestone the feeders of water amounted to 3,000 gallons per minute, but this was soon dammed back by a casing of cast-iron tubbing, which was carried from the little seam of coal above mentioned to within seventy-eight feet from the surface.

For a considerable distance into the coal-measures the undertaking appeared very unpromising, as a

greater thickness of barren strata was pierced than had ever been encountered previously. A new feeder of water was met with at the depth of 1,000 feet, requiring fresh pumps and a fresh outlay of money. In the eyes of most men the prospects of the enterprising adventurers seemed dark indeed; by many of the coal-owners the project was denounced as hopeless. But the Messrs. Pemberton boldly persevered, sinking deeper and deeper, until in February, 1834, their pluck was rewarded by the shaft reaching a seam of coal of considerable thickness and value at the depth of 267 fathoms from the surface. This seam was found to be identical with the Bensham seam of the Tyne, or Maudlin seam of the Wear, and the shaft was afterwards carried down further to the still more valuable Hutton seam, which was sunk to in April, 1846, at a depth of 287 fathoms, or 1,720 feet from the surface. The winning of this colliery is stated to have cost about 100,000l.

In the meantime a number of other sinkings had been carried down through the limestone. The first attempt made at Haswell, by the Haswell Coal Company, was abandoned, after an expenditure of 60,000l., on account of the stratum of quicksand encountered by the shaft, at the bottom of the limestone, proving twenty fathoms thick. The second attempt was more fortunate. By means of boring, a spot was found free from quicksand, and here a shaft was sunk which

reached the Hutton seam in March, 1835, after five years' labour, at a depth of 155 fathoms.

Coincidently with the above sinking another was made in the northern part of the same township by Colonel Braddyll and partners (the South Hetton Coal Company), which, after piercing fifty-seven fathoms of limestone and five fathoms of sand, reached the Hutton seam, at a depth of 180 fathoms, in 1833.

A few years later the same company, being desirous to increase their powers of producing coal, commenced to open out another colliery, at Murton, which proved one of the most difficult and costly winnings ever effected. In the beginning of 1838 two pits, each fourteen feet in diameter, were begun, and carried forward simultaneously, at a spot where it had been ascertained by boring that the limestone was seventysix fathoms thick, and the sand below from five to six fathoms. The feeders of water encountered in piercing the limestone were successively tubbed off, so that immediately previous to the bed of sand being reached the shafts were free from water. On the 26th of June, 1839, when one of the shafts approached the top of the quicksand, the sand-feeders burst upwards through four feet of strong limestone which intervened; and before the pumps could be heaved up they were all choked, and ten feet of sand deposited in the bottom of the pit.

It having been found that the engine power at this