MR MILNE ON THE MID-LOTHIAN AND EAST-LOTHIAN COAL-FIELDS. 



323 



as to the materials of which it is composed, and the height of its base above the 

 sea, before leaving this branch of the subject. 



In some places, this bank has been formed on the boulder-clay ; — there it is 

 always highest and steepest, because the clay is hard and strong, and is not easily 

 affected by atmospheric influences. In this respect, it is more enduring even than 

 rock, for it is impervious to water, and therefore is not acted on either by dry- 

 ness or moisture, nor is it afiected by variations of temperature. At some places, 

 however, the bank is low, and indeed scarcely discernible, — as at Portobello. 

 There it consists of the fine brick-clay, which is not so strong or stiff as the boul- 

 der-clay, and can be more easily worn down by ordinary atmospheric action. 



I wish I could speak with certainty and precision regarding the height of the 

 base of this bank above the sea. I cannot yet do so ; though I expect ere long to 

 have a table completed, affording this information for every part of the coast. I 

 may state generally, that, whilst its average height is between 30 and 40 feet 

 along its whole extent, I have reason to think it rises towards the west. I think 

 it is 15 or 20 feet higher at Falkirk and Bannockburn than it is at Aberlady. 



7. I proceed next to describe the uiyper covering of gravel and houlders, which 

 has been deposited even more recently, than the beds of sand which contain frag- 

 ments of existing sea-shells. 



Before alluding to the contents of this deposit, or the extent of country it 

 covers, I should wish to notice two or three localities, an inspection of which 

 must satisfy any one, not only that it exists, but that it is also more recent than 

 the deposit of sand and shells of which I have just concluded the description. 



About a mile to the west of Gosford, the seat of the Earl of Wemyss, there 

 is, near the shore, a section that may be represented by the following figure : 



1. is a quantity of sand, probably blown. 



2. is a stratum of boulders and gravel. The boulders are from 3 to 8 inches in diameter. They 



are rounded. They consist chiefly of greenstone, and of a peculiar kind, which occurs in 

 situ on the beach about a mile to the west ; it is about 2 feet thick. 



3. is the stratum of shells mixed with pebbles and gravel. The shells are much broken. They 



consist of oysters, wilks, lempits, &c. The lowest part of this bed is 7^ feet above high- 

 water mark. 



4. are strata of shale, &c. Their base is washed by the sea at high-water. 

 .^. the line of high water. 



