Coal. 



229 



of a single plant, whose form can be distinctly traced ; though it is 

 always broken into fragments, whose length rarely exceeds two feet, 

 At Whitmore's ferry, in Sunderland ; in the north part of South Had- 

 ley, and on the north bank of Westfield river in West Springfield, 

 the coal is highly bituminous ; though least so, at the last named local- 

 ity. But at Turner's Falls, in Gill ; at the Southampton lead mine, 

 and at Enfield Falls, (Connecticut,) it is anthracite. At the junction 

 of this same formation with the greenstone at Berlin, in Connecticut, 

 Dr. Percival has described a vein of bituminous coal penetrating the 

 greenstone. He says, however, that " it more usually has the ap- 

 pearance of cinders so mixed up with siliceous matter as to be hardly 

 combustible." 



It becomes an interesting enquiry, whether local circumstances 

 will enable us to explain why the coal at some of these localities is 

 bituminous, and at others anthracite. " We know," says Prof. Al. 

 Brongniart,* " that the coal which is in contact with the veins or 

 dikes of basanite, or trap, that traverse it, and that which approaches 

 masses of porphyry, is less bituminous than other portions of the bed, 

 and that it even loses all its bitumen, and in passing to the state of 

 anthracite, exhibits, as it were, a kind of vitreous texture, &c." Few 

 geologists will now doubt but the proximity of granite produces a 

 similar effect. Now at Turner's Falls we know that a large mass of 

 trap is not far from the coal ; and at Southampton, that granite is still 

 nearer ; and hence we should expect the coal at these places to have 

 lost its bitumen. I am not aware, however, of the proximity of either 

 of these rocks to the coal at Enfield Falls ; though ignorant of its 

 particular location. At Sunderland and South Hadley the trap is so 

 far distant, that we are not surprised to find bitumen. The existence 

 of bituminous coal, however, in the trap at Berlin, Ct. is quite re- 

 markable : and the fact that a portion of it is converted into psuedo- 

 cinders, proves that heat does not necessarily drive out the bitumen. 

 The contorted condition of the strata at the locality of coal in West 

 Springfield, renders it quite probable that trap rock exists a short dis- 

 tance beneath the surface. The pretty uniform dip of the strata, 

 where they are laid bare in that town several miles in width, by 

 Westfield river, is from 15° to 20° east. But at the spot just referred 



* Tableau Des Terrains, &c. p. 283. 



