GREAT NORTHERN COAL-FIELD.
This coal-field is perhaps the largest in England. It was the first developed, and is of the greatest im portance to the British coal-trade, since it furnishes nearly one-fourth of its production. The area of this field is calculated at 750 square miles, including only 50 square miles under the sea; but good authority, in cluding the eminently practical opinion of Nicholas Wood, Esq., places half of the field or more under the North Sea, which would swell the area to 1400 square miles.
This field is generally known as the Newcastle coal field, and is located in Durham and Northumberland counties. It extends from the river Tees in the south to the Coquet in the north ; a distance of 48 miles, with a maximum breadth of 24 miles, or a mean of nearly 16 miles. The deepest coal that has been proved is the Hutton Seam, in the Monk-Wearmouth Pit,which is 1800 feet below the level of the sea, and its mouth one mile from its shores, the coal still dipping east, or under the sea. Below the Hutton are the Harvey and the Rock-.
well seams, besides some five or six others, not now considered workable; the whole occupying some six or seven hundred feet of coal measures. Accom panying will be found a vertical section of this coal-field near the mouth of the river Wear, at the Monk-Wearmouth pit, which is 1800 feet below the sea-level, shown by the water-line crossing some hundred feet below the pit's mouth, on a level with the Wear, which enters the sea at Sunderland, one mile from this point. We have numbered the strata in the same manner as adopted in the Paleozoic strata of the Appalachian formation, figure 2, Chapter II. No. XIII. represents the coal measures; No. XII. the great
conglomerate, or, as known in England, the millstone grit; No. XI. the great Carboniferous limestone, containing the upper and lower coal series. No. X. is the lower Carboniferous limestone,—the scar limestone, contain ing the lower coal series of the English formations, and synonymous with our protocarboniferous, or false coal measures. No. IX. is the famous "old red sandstone." Above the coal, No. XIV., in this section, is the Permian formation, not shown in our Appalachian column, though probably existing. This is the new red sandstone, and the magnesian limestone, so peculiar to the great English coal-fields.
This Permian formation extends from the vicinity of Tynemouth, about the middle of the coal-field, to its southern extremity, on the Tees,—cover ing about one-fourth of the coal-field from 100 to 300 feet deep.
Through this, as will be noticed, the Monk-Wearmouth pit is sunk. It frequently happens that the cost of sinking through the Permian is enor mous, owing to the sandstone underlying it being in the shape of quick sand, or full of great water-seams, which drain an immense area of coun try, or, perhaps, may be fed from the sea.
In one instance, at the "winning" of Murton colliery, 9000 gallons of water per minute were encountered in this sandstone, requiring the exer tion of 1584 horse-power to work the pumps. The first attempt at the Haswel pit, or "winning," was abandoned after the expenditure of $300,000, in consequence of the excess of water; and in another case over $1,500,000 were expended in establishing a single colliery.