MR MILNE ON THE MID-LOTHIAN AND EAST-LOTHIAN COAL-FIELDS. 321 



It consists of a fine sand at the foUowing places, viz. Caroline Park, PortobeUo, 

 Musselburgh, and Seton, varying in thickness from two to eight feet. The layers 

 are in general horizontal, or else dipping towards the sea, in accordance with the 

 subjacent clay on which it rests. At all the places just mentioned, there is at the 

 bottom of the bed, a quantity of boulders, some of which are of enormous size. 

 They are generally greenstone and basalt, though I have remarked also blocks of 

 limestone. At PortobeUo, these blocks are dug out and removed, in order to get 

 at the brick-clay, the surface of which is covered by them. Among these blocks 

 are quantities of marine shells, all apparently belonging to the same species 

 now existing in the Frith of Forth. 



But this deposit does not every where consist of sand. Accumulations of 

 very fine gravel are occasionally met with, mixed up vdth prodigious quantities of 

 marine shells. The shells are generally broken and shattered, in the same way 

 as they usually are on a sea-beach. I do not say that all the sheUs which exist 

 in this deposit, are to be found in the present sea; — because I have not yet col- 

 lected a sufficient number to enable me to say so. It is quite possible, that among 

 these shells in this particular deposit, as in the one previously described, some 

 species may exist which are now extinct. * 



I have walked along the whole shore, from St Abb's Head round by Dunbar, 

 North Berwick, Aberlady, Cockenzie, and Newhaven, to Queensferry, and more- 

 over traversed the greater part of the Carse district from Falkirk to beyond Stir- 

 ling. I did this, in order to coUect facts which might throw light on the import- 

 ant geological question, whether any proofs exist in this part of the island of a 

 recent change in the respective levels of sea and land. When I commenced this 

 investigation, my object chiefly was to discover the localities of sea-shells, and 

 their exact height above the present level of the sea. I had not gone far, before 

 I was much struck by the occurrence of the high bank formerly alluded to, run- 

 ning everywhere nearly parallel with the existing shore ; — but it was not tni a later 

 period of my investigations, that I perceived the connection of that bank with the 

 subject I was examining, and the far greater importance of ascertaining the height 

 of its lase above the sea, than that of the shelly bed occurring between it and the 

 sea. 



In general, this bank is distant from the present line of high- water mark 

 about 300 yards ; whilst, at other places, it is close upon the sea, and occcasion- 

 aUy ceases altogether. I avoid at present offering any explanations of these facts. 

 I would only here add, that the bank is everyivhere most inland, in those parts of 

 the coast where the sea is shallow, and where, consequently, it recedes at every 

 tide to a considerable distance. Along the coast near North Berwick, where the 



• Mr Smith of Jordanhill is of opinion, that several of the shells he has found in the superficial 

 deposits in the west of Scotland belong to extinct species — to the number of twelve or thirteen. 

 VOL. XIV. PART I. S S 



