Coal. 



227 



good ore have been obtained. A new adit is now in progress, which 

 will strike the bed of copper ore about 200 feet below the surface. 



Although nothing but sandstone is found where this bed of ore 

 crops out, yet a greenstone ridge appears a few rods distant, and the 

 dip of the bed is towards the greenstone, and must therefore pass un- 

 der it, or intersect it. 



Native copper has been found in small pieces at this mine. 



Coal. 



It has long been known that coal was found in the sandstone of 

 Connecticut valley : and on this fact mainly has the opinion been 

 based, that a real coal formation exists there. But I think I have 

 satisfactorily shown that this formation must be referred to the new 

 red sandstone group. Yet if this be admitted, shall we infer that 

 there is no hope that it may contain coal in such quantity, and of such 

 quality, as to be useful for fuel ? A few years ago, geologists would 

 have peremptorily decided this question in the affirmative : but in 

 the present state of their science, it seems to me we may at least 

 reasonably hesitate, and perhaps draw a contraiy inference. It is 

 now generally admitted that all coal has a vegetable origin ; and 

 that simply by the long continued action of water, under certain cir- 

 stances vegetable matters pass into the state of peat, next into lignite, 

 then into bituminous coal, and finally into anthracite : though this last 

 substance more commonly perhaps, results from the action of heat on 

 bituminous coal : and if the heat be powerful enough, even plumbago 

 may be produced ; " as wood has been (says Dr. Macculloch,*) in 

 my experiments, and as coal is daily, in the iron furnaces." Such 

 a change he found, in one case at least, produced upon common coal, 

 in the vicinity of a trap dyke : hence he reasonably infers, " that 

 even the plumbago of the primary strata, no less than the anthracite, 

 might as well have originated in vegetables, as that each of these 

 should owe an independant origin to elementary mineral carbon." 



According to this theory, why may we not hope to find large 

 quantities of workable coal in any formation where we find it in 

 small quantities ? For the same causes that could produce it in thin 

 beds, might reasonably be supposed adequate to the production of 

 large masses. Anthracite is found in almost every rock from lias to 

 gneiss ; and bituminous coal occurs in the oolitic and new r«d sand- 



* System of Geology, &c. Vol. 1. p. 298. 



