Various attempts have been made to develop the coals of New England, by practical as well as those who were not practical men; but they have all resulted in failure, not for the want of means or experience (except in a few cases), but because the beds were too unreliable and irregular to permit the production of coal with economy, or in competition with mining operations in the reliable coal-beds of Pennsylvania.
We give below a section from Taylor's Statistics, across the Portsmouth basin in Rhode Island, from Mount Hope Bay to Narraganset Bay, looking north.
The centre of the basin, or ti te measures overlying the coal, appear to consist of altered sedimentary ro,,Is metamorphosed from the common slates and sandstones to the crystalline, sedimentary, or metamorphic, by heat in water. The coal rests on a coarse conglomerate, made up with the fragments of primitive rocks, but singularly impressed with fossil forms peculiar to later ages; thus presenting evidence of the existence of the older rocks in superior position, or at greater elevation than the basin in which this coal was found. There are three seams of coal outcropping on the western side, dipping towards the centre of the basin, at an angle of 45°, but flattening towards the centre. They are all much crushed and irregular. The average size of these seams is about 3 feet; but they are constantly liable to sudden changes, and vary from a few inches to as many feet in a short distance.
The outcrops frequently yield plumbago, and occasionally nests of almost pure graphite are found in the coal-beds. That near the surface is col lected and sold as black lead, under the name of "British lustre," and makes a good polish for stoves, &c.
Notwithstanding the defects and irregularities of these coal formations, the coal when in its best condition is very good, and presents the following analysis:— which indicates a true anthracite ; and most of our geologists who have examined this region pronounce the coal of great local value. Professor Hitchcock says, "Ere long, the anthracite of Rhode Island, and even that of Worcester, will be considered by posterity, if not by the present gene ration, as a treasure of great value." And in publishing his final report in 1840, he says,— "I became satisfied that a part of this region was a true coal formation, and so marked it on the map. I now go a step farther, and maintain that
the whole of this tract, embracing not less than 500 square miles, is a genuine coal-field that has experienced more than ordinary metamorphic action. The metamorphic action to which this deposit and the coal have been subject is twofold, viz.: first, mechanical ; second, chemical.
"The mechanical forces seem to have operated on the strata containing the coal in a lateral direction, so as not only to raise them into a highly inclined position, but also to produce plaits or folds such as would be formed if several sheets of paper lying upon one another were taken into a man's hands and by pressure on the opposite edges were crumpled so as to form ridges and hollows.
"The chemical metamorphoses which these rocks have experienced con sist mainly in such effects as heat would produce.
‘,. . . . The evidence seems very strong on which I base the conclusion that the Bristol and Rhode Island deposits, with vegetable remains, pos sess much the age and character of a true coal-field as the Carboniferous period of the geologists.
"I. In the first place, the general outline of the surface over this field corresponds with a regular coal-field or basin.
"II. The rocks correspond essentially to those of the coal measures.
"III. The number, position, strike, dip, and general character of the beds of coal already discovered in the district under consideration render it probable that it is all one coal-field, or essentially one.
"IV. The character of the vegetable remains found in connection with these coal-beds make it almost certain that they belong to the coal measures of the Carboniferous period." Dr. Jackson thinks that the coal of Mansfield, in Massachusetts, may be worked with much profit if pursued with skill and judgment.
But the difficulty in the way of profitable mining in these New England coal-fields will be evident to practical men. Most of the coal lies below water-level, and can only be reached with long, deep slopes or shafts; and, as the beds are thin, a great distance must be opened out to produce even a small amount of coal.