MR MILNE ON THE MID-LOTHIAN AND EAST-LOTHIAN COAL-FIELDS. 295 



true that Arthur Seat, and the other traj^-hills in that neighbourhood, are beyond 

 the precincts of the present coal-field ; but there is the clearest evidence, that be- 

 fore the sedimentary strata had been thus burst through and shattered, they had 

 extended over all the district now occupied by these trap hills. This is not the 

 proper place for enumerating the facts which shew this ; and, therefore, I will 

 merely state the results. 



(1.) Seams of coal, ironstone, besides various other strata, such as usually oc- 

 cur in the Dalkeith coal-basin, are found to the north and west of these trap 

 hills ; and, generally speaking, they all rise towards these hills. For example, 

 on the east side of the Calton Hill, beds of conglomerate or puddingstone, which 

 are the very lowest members of the series, if they do not belong to the old red 

 sandstone formation, are to be seen dipping towards the east, or away from the 

 hill ; and they increase in dip as they approach the top of the hill. To the east 

 of the Castle rock the strata dip in a similar way. On the north side of this rock, 

 the strata dip noj'th, — as may be seen in the Prince's Street gardens, — as was seen 

 when Hanover Street was built,* and as was seen during this winter (1837-8) in 

 Castle Street. f In the Water of Leith, above and below St Bernard's Well, beds 

 of shale occur — dipping north ; and some years ago, coal was worked in Mr Rae- 

 burn's property a little to the east of St Bernard's Crescent. In the rivers and 

 burns near Colinton and Slateford, many strata of shale and sandstone, including 

 thin seams of coal, occur dipping to the west. 



(2.) A still more unequivocal proof that the trap hiUs of Edinburgh and its 

 neighbourhood were ejected, after the formation of the coal strata, is afforded by 

 fragments of these strata found on the tops of these hiUs, enveloped in the trap. 

 On the SE. part of A rthu?^ Seat (and at a height of from 400 to 500 feet above 

 the sedimentary rocks), there occur masses of sandstone, conglomerate, and lime- 

 stone, which have been torn from the basin, and carried up by the trap. On 

 the top and at the west side of Craiglockhai^t Hill, there are imbedded masses 

 of sandstone. X In the Calton Hill pieces of glance-coal have been found, which 

 are supposed to have been taken up by the trap in its passage through some 

 coal seams. 



* The strata here consisted of sandstone, shale, and limestone. A mass of greenstone had in- 

 truded itself among them, and formed several fissures, which were filled with trap. This fact I be- 

 came acquainted with by a sketch, taken by John Clerk of Eldin, the intimate friend of the celebrated 

 Dr HuTTON. This sketch is now in the possession of Mr Clerk's sou, William Clerk, Esq. Ad- 

 vocate ; and he has besides it several others, also taken by his father, which are of high geological in- 

 terest. On ray suggesting that he would confer a great benefit on science if he would allow these sketches 

 to be published, he expressed his willingness to do so, and stated that he would be happy if the Royal 

 Society of Edinburgh thought them deserving of their notice. 



■f At this spot, situated in North Castle Street, felspar porphyry, of a white colour, and containing 

 iron-pyrites, was found. 



X I state this fact on the authority of Professor Forbes. 



