"No idea can be formed of the importance of the American coal seams until we reflect on the prodigious area over which they are continuous. The elliptical area occupied by the Pittsburg seam is 225 miles in its largest diameter, while its maximum breadth is about 100 miles, its superficial extent being about 14,000 square miles. "The Apalachian coal-field extends for a distance of 720 miles from northeast to southwest, its greatest width being about 180 miles. "The Illinois coal-field is not much inferior in dimensions to the whole of England."--Lyell's _America_, vol. ii., p. 31. "It was the first time I had seen the true coal in America, and I was much struck with its surprising analogy in mineral and fossil characters to that of Europe; ... the whole series resting on a coarse grit and conglomerate, containing quartz pebbles, very like our millstone grit, and often called by the Americans, as well as the English miners, the 'Farewell Rock,' because, when they have reached it in their borings, they take leave of all valuable fuel."--_Ibid._, vol. i., p. 61.] [Footnote 153: See Appendix, No. XXI. (see Vol II)] [Footnote 154: Professor Kalm visited the iron-works of St. Maurice in 1748, eleven or twelve years after their first establishment. "The iron-work, which is the only one in the country, lies three miles to the west of Trois Rivieres. Here are two great forges, besides two lesser ones to each of the great ones, and under the same roof with them. The bellows were made of wood, and every thing else as in the Swedish forges. The ore is got two and a half miles from the iron-works, and is carried thither on sledges. It is a kind of moor-ore (Tophus Tubalcaini: _Linn. Syst. Nat._, lib. iii., p. 187, note 5), which lies in veins within six inches or a foot from the surface of the ground. Each vein is from six to eighteen inches deep, and below it is a white sand. The veins are surrounded with this sand on both sides, and covered at the top with a thin mold. The ore is pretty rich, and lies in loose lumps in the veins of the size of two fists, though there are a few which are near eighteen inches thick. These lumps are full of holes which are filled with ocher. The ore is so soft that it may be crushed between the fingers. They make use of a gray limestone, which is broke in the neighborhood, for promoting the fusibility of the ore; to that purpose they likewise employ a clay marl, which is found near this place. Charcoals are to be had in great abundance here, because the country round this place is covered with wood which has never been stirred. The charcoals from evergreen trees, that is, from the fir kind, are best for the forge, but those of deciduous trees are best for the smelting-oven. The iron which is here made was to me described as soft, pliable, and tough, and is said to have the quality of not being attacked by rust so easily as other iron. This iron-work was first founded in 1737 by