The Tyne district was formerly the most important in the Northern Coal-field, both as regarded the value of its coal seams and the number of its collieries in operation, but it is at present excelled in finer, harder, and better qualities by the Wear and a portion of Bishop Auckland, called the Tees Wallsend district. Nevertheless, it still retains the first position upon the official lists, published by the Committee of the Coal Trade, as it still comprises the largest number of collieries. There appear in the circulars issued by the Coal Trade Committee, at the present time, the names of 134 collieries, and most of them have several different pits or working shafts. There are sixty-four collieries in the Tyne district, twenty-four of which are distinguished for producing good household coal, the like number (twenty-four) a coal suitable for coking or the manufacture of gas, six collieries producing coal suitable for steam purposes, and the remainder an article of a promiscuous character between household and coking coal.

These characteristic differences in the quality of coal shall be afterwards investigated and explained, as they have an important bearing on the consideration of the general subject of the coal trade and the probable duration of the coal-field.

Four collieries, all supplying steam coal, are enumerated in the Blyth district, but they ship coals also on the Tyne. Three extensive collieries, supplying household coal, belong to the Seaham district. On the Wear there are sixteen collieries, all of which, excepting one, produce household coal. And in the Tees district there are twenty-one collieries, ten of which yield household coal.

The information, with respect to the various collieries in the coal district, set forth in the subjoined table, has been collected with great care, and as a statistical record of the present state of the trade in this part of the kingdom will be regarded with interest and importance. (See Appendix.)

It has been calculated there are about fifty-seven different seams of coal in the Newcastle Coal-field, varying in thickness from one inch to five feet five inches, forming an aggregate of seventy-five feet seven and three-quarter inches, but some of them are so thin that they cannot be worked so as to be remunerative, on which account their existence is of little consequence. Judging from past experience and present prospects generally, a seam, to defray the expense of working and leave a return for interest of capital and risk, ought not to be less than from thirty inches to near three feet in thickness.

Seams of coal have been in some cases wholly excavated, or so much has been removed as could be done with safety. Formerly much more coal was left in the seams as irrecoverable than in the present day, as we have now a much more efficient plan of working than was in existence during many hundreds of years. In such cases the mine has been either lost or abandoned, or recourse has been had to other seams in the same mine of inferior quality which are worked at greater expense, while the produce of them will not bring so high a price in the market. The profits, if any, in such cases, must be extremely precarious and uncertain. The following is a list of what may be termed workable seams in the Northern Coal-field, according to the designation they receive in the Wear district:— High Main, Five-quarter, Main coal, Bensham, Hutton, Beaumont, Stone coal, Low Five-quarter, Three-quarter seam, and Brockwell.

These several seams vary in quality as well as thickness, and some of them are known by different names in different districts; thus the Bensham seam of the Tyne is known as the Maudlin seam of the Wear; the Beaumont or Harvey seam is known in Towneley Colliery as the Towneley seam; and in Wylam Colliery, as the Main coal seam; and so on of others. Even some parts differ in quality from others in the same seam, so that great diversity exists in that respect throughout the entire district of the northern coal measures.

The High Main seam of the Cramlington district separates into two at Hetton, and is there called the Three-quarter seam; unites at Pontop under the name of Shield-row seam, and again at Auckland takes the name of the Three-quarter. The Grey seam of the Cramlington district forms the Metal coal seam, and the Stone coal seam at Sheriff-Hill, uniting to form the Five-quarter seam at Hetton, running close to the Brass Thill seam at Pontop, still preserving its name, and rising in the strata in the same name in the Auckland district. The Yard coal seam of the Cramlington district retains the same name at Sheriff-Hill, becomes the Main coal seam at Pittington, Hetton, Haswell, and Houghton-le-Spring, the Brass Thill at Pontop, and the Main coal at Black Boy in the Auckland district.

The Bensham seam of the Cramlington district is known as the Maudlin at Sheriff-Hill, as the Low Main at Hetton, and runs into the Hutton seam at Pontop; and is marked by Mr. Greenwell in the Black Boy Colliery as Surtees Seam, at a very deep boring at Black Boy Old Pit. But this seam wants identification. There appears to be less doubt by mining engineers, as to the present Five-quarter and Main coal seams being the same seams as are so-called in the Wear district, which district, namely, Tees Wallsend, will be seen on the map only of small extent. These seams are now worked not only at Black Boy and Tees Wallsend, but at Coundon, Leasingthorne, Eldon, and Adelaide Collieries, and yield a superior quality to any other Five-Quarter or Main Coal, or in fact the Hutton seam, besides there is a great thickness of good coal of proper hardness.

The Five-quarter seam of the Cramlington district divides and forms the Six-quarter, and the Five-quarter at Sheriff-Hill the Brass Thill seam at Pittington, which unite there, and run together into the Hutton seam at Pontop Colliery. The Low Main seam of the Cramlington district retains the same name at Sheriff-Hill, becomes the Hutton seam at Hetton, and the Main coal at Pontop, dividing into two thin seams in the Auckland district.

In Towneley Colliery, in the Ryton district, the coal is worked in the Beaumont, which is the Harvey or Towneley seam, the Stone coal, Five-quarter, and the Brockwell seams. The Tilly and the Hand seams, between the Beaumont and the Stone coal, and the Three-quarter, between the Five-quarter and the Brockwell, are not of workable thickness. These are all coke and gas coal. The Stone coal and the Five-quarter seams run together in patches at Towneley Colliery and other places, and they form the Busty Bank seam of the Pontop district.

The Three-quarter seam of the Sheriff-Hill district is twenty fathoms above the High Main seam.