MR MILNE ON THE MID-LOTHIAN AND EAST-LOTHIAN COAL-FIELDS. 279 



The only proper foundation for any attempt to explain the laws of natui-e, is 

 an extensive collection and accurate classification of facts. If this is true in re- 

 gard to all the physical sciences generally, it is peculiarly so with regard to Geology, 

 in which most of the relations are extremely complicated, and not easily discovered 

 or observed. Therefore it is that, in describing so minutely the subjects noticed in 

 this first part of my memoir, — and above all, in assorting together in a conve- 

 nient and visible form the facts therein described, — ^my object has been to lay a 

 foundation, on which the explanations to be offered in the next part of the me- 

 moir can safely rest : for the same process of reasoning which has been so success- 

 fully employed in explaining the phenomena of Chemistry and Astronomy, must, 

 if properly applied, prove no less successful in explaining the phenomena of 

 Geology. 



II. EXPLANATORY PART. 



Having concluded my narrative of facts, descriptive of the rocks of the dis- 

 trict, I proceed next to offer some remarks, with the view of explaining these facts. 

 In doing so, however, I will not prevent myself from noticing any additional cir- 

 cumstances, necessary for illustrating these explanations. 



Before beginning to reflect upon the various phenomena of the district, it is 

 proper to have some idea of the geological epoch when the strata existing in it 

 were formed, and to consider their relation to the neighbouring hilly ranges. 



The coal-measures of the Lothians are bounded on the south by the Lam- 

 mermuir Hills, which consist (as is well Icnown) almost entirely of grej^wacke 

 strata. I say almost entirely ; for amongst them we find great masses of trap, as 

 at St Abb's Head, Oldhamstocks, Cockbumlaw, Fassney, and Soutra Hill. At 

 the three places last mentioned, — whole hiUs of granite exist, — a fact not generally 

 knowm. Now, along the whole north flank of this range of hills, there occur the 

 same description of strata as those which compose the district more immediately 

 the subject of the present memoir. It is true that the coal-seams and lime-strata, 

 where they approximate these hUls, are scarcely if at all woi-kaMe. It is only at 

 La Mancha, Middleton, and one or two other places, that they become thick 

 enough for that pm-pose. But there can be no doubt that the thin seams of 

 coal and limestone worked there belong to the series of measures previously 

 described ; and there is scarcely any doubt that these thin seams of coal and lime 

 can be recognised and identified as particular members of that series. Near 

 Blackshiels, for example, there are two or three thin seams of coal, which lie un- 

 der the Crichton Dean limestone. These coal-seams have been found under the 

 same limestone at other places, as at Middleton, at Tr-abroom (in the parish of 

 Gladsmuir) at Alder stone, at Coalstone, at Moreham, at Amisjield, at Dunglass, 

 " and vai-ious other localities in East-Lothian. Moreover, at many of these localities. 



