E.. Hitchcock on the Coal of Bristol Co., and R. Island. 335 
The geologist will notice two circumstances of importance in 
the preceding facts; one is, that there is a tendency to a northeast 
and southwest direction in the beds of coal. The other is, that 
where horizontal drifts of any considerable extent have been car- 
ried across the strata, several beds have been crossed. The ex- 
ceptions in the dip can easily be explained by the proximity of 
the older crystalline rocks, which may have greatly changed the 
direction, at least for some distance ; and the opposite dips observ- 
able in some cases, may be referred to the same cause, or perhaps 
to an anticlinal axis of older rocks, which I have some reason to 
Suspect, may cross this coal field in a N. E. and 8. W. direction. 
It seems to me difficult to avoid the conclusion, that these dif- 
ferent beds, scattered as they are so widely, all belong to one and 
the same coal field ; although denudation or vertical movements 
may have rendered some parts of it much less productive than 
others. The strike and dip, as well as the number of beds, cor- 
respond as well to other coal fields as we ought to expect, when 
Wwe consider the great amount of metamorphic action which has 
here been exhibited. 
It ought to be known, too, in this connection, that this region 
is densely covered by accumulations of drift, and the sand and 
gravel of ancient sea beds. Especially is this the case where the 
rock is the softest,—that is, the black shale—which contains the 
coal beds. Hence rocks rarely show themselves at the surface, 
and the wonder is, that so many beds of coal have been discovered, 
rather than that no more have been found. The digging of wells 
and other excavations have been the principal means of bringing 
them to light; nor will any reasonable man doubt that probably 
many more are concealed beneath so thick a coating of drifted 
materials, 
IV.—The character of the vegetable remains found in connec- 
tion with these coal beds, make it almost certain that they belong 
to the coal measures of the carboniferous system. é, 
[Figures of species of Stigmaria, Calamites, Pachypteris or 
ontopteris, and Neuropteris, on two plates, are here referred to. } 
I might add several other species of plants peculiar to the coal 
formation, and found in this field. But it seems to me unneces- 
sary. Those already exhibited appear to settle the question as 
to the true place of these deposits, in the geological scale. 
geologist would think of putting them in any other part of the 
Series than the carboniferous. I have not, indeed, met with any 
specimens in these rocks, of Sigillaria and Lepidodendra, which 
are common inthe eoal rocks of Pennsylvania and Ohio. But it is 
more easy to explain their absence from a real coal field, than the 
presence of so many other plants, identical with those of the coal 
measures, in any other formation. 
