NOTES ON THK GEOLOGY OP EAST LOTHIAN AM) HKUWICKSHIRE. 1U9 



4th. — Within the period of the two preceding groups, there seem to have 

 been extensive tracts of elevated land, covered with the ancient plants of the 

 carboniferous era; of this we are certain, that the isolated coal beds which 

 characterize this shore, were deposited in regular order on the preceding group. 

 The underlying strata of Old Red Sandstone show a regular gradation from 

 the conglomerate to a fine quartzose Sandstone; but before passing finally into 

 the coal measures, we find the same pebbles, or rather fragments of which the 

 conglomerate is composed, imbedded in lime, and forming a calcareous con- 

 glomerate, after which succeed the ordinary beds of lime, shales, and sandstones. 

 There is, therefore, no sudden change from the one set of strata to the other. 

 The transition is perfectly gi-adual, and in perfect harmony with those theories 

 resulting from the researches of modern geologists, which all tend to demon- 

 strate that the old hypothesis of vast and sudden convulsions, revolutionizing 

 at stated epochs the whole surface of the globe, have no place in the economy 

 of nature, where every thing is, and ever has been, regulated by laws, whose 

 grand characteristic is the principle of a slow but certain progression."' 



5th. — A second great mineral axis now came into force, ranging nearly east 

 and west, and elevating and tilting the strata of the Old Red and Carboniferous 

 groups. We see this axis in the trap rocks about Dunbar, and at the Cove, 

 and it explains without doubt the high inclination, the north-eastern dip, and the 

 occasional alterations of these beds. In attempting to trace the nature of this 

 change, we may suppose the rocks of the district to have presented three 

 different phases in succession. First, the sedimentary rocks would be deposited 

 in a level position, and the surflxce would then form one continued subaqueous 

 plain. Second, the eruptious of trap at several localities would fissure and tilt 

 the beds, throw up some portions, and depress others: the surface would then 

 exhibit a vast assemblage of heights and hollows, bounded by mural precipices. 

 Third, diluvial currents would sweep away the more tender and more exposed 

 strata, wearing down all the prominent parts, till its action was arrested by the 

 firmer rocks, especially by beds of trap. These beds of trap, though origi- 

 nally injected at a considerable depth, would now occupy all the salient points 

 of the surface, and give the country its peculiar physiognomy, as is the case 

 in the inunediate neighbourhood of Dunbar. It has been here assumed that 

 the eruption of the trap rocks took place simultaneously, although it may 

 have occurred at different periods. My object, however, is not so much to 

 paint the condition of the whole surface at any one time, as to convey an 

 idea of the sutn of the changes which it has undergone from the causes re- 

 ferred to. If these views be even approximately true, they help us to account 

 for the very interesting phenomena of this coast; but I admit they may be 

 open to doubt, as my examination of this coast, in extent about thirty-one 



* Perhaps it may be necessary that I should guard this statement; it is not to be supposed 

 tliat I do not admit that there have been forces in operation greater than any that we now witness 

 on our globe, giving those physical features to our planet, which add so much to its beauty and 

 our enjoyment; but I do not agree with those who state that every group has been ushered 

 in and closed with periods of violent disturbance. 



