112 Lord Greenock on the Coal Formation of the 
sures, enveloping and carrying up in its passage large fragments 
of the broken strata, and exhibiting all those signs of violence 
and intrusion which such rocks so frequently display; or they 
may sometimes have been followed by sufficient intervals of re- 
pose, to have admitted of new deposits of sandstones, shales, or 
limestones, above the produce of each successive eruption, and in 
this way the interstratification of the trap with these beds, may 
be accounted for in those cases in which few, or no marks of dis- 
turbance are visible. 
To the effects of Plutonic action during the carboniferous 
epoch, which may have been in activity for ages under the pres- 
sure of the superincumbent ocean, may be referred, besides the 
dislocations and undulations by which the strata are broken and 
distorted, those gradual risings and depressions of the land which 
‘it seems necessary to admit, in order to explain the alternations 
we so frequently meet with in the coal-measures, of beds teeming 
with the remains of marine animals, with others in which they 
are totally wanting, or that contain only those of terrestrial plants. 
In fact, they appear to have been the means of gradually prepar- 
ing the countries occupied by these deposits, for the purposes 
which, in after times, they were destined to fulfil, when, by a re- 
newal of the same agency, both descriptions of rocks were simul- 
taneously lifted up above the waters in their consolidated state, 
to the positions they relatively occupy at the present day. 
Nor is the infinite wisdom that has presided over the forma- 
tion of our planet in this, as well as in every period, apparent on- 
ly in the changes that have been thus produced in the configura- 
tion of its surface; for when we consider the various ways in 
which these subterranean convulsions may have influenced the 
chemical changes and combinations of the vegetable, animal, and 
gaseous matters, through which the coal itself has been brought 
into its present combustible form, they evidently appear to have 
been the chief agents employed by the wise design of a benefi- 
cent Providence, in the modification of this important deposit, by 
