in the Neighbourhood of Edinburgh. 247 



that a stratum had been pierced, consisting of small water-worn pebbles of quartz, 

 cemented by a soft greenish and yellowish argillaceous substance, apparently decom- 

 posed trap or felspar. The argillaceous substance of the conglomerate rock appear- 

 ed to me indicative of some igneous eruption, though perhaps remotely situated, 

 which must have taken place not long after the deposit of the Burdiehouse lime- 

 stone. 



The sandstone of Straton quarry is of a yellowish, or yellowish-brown colour, and 

 of a hardness which recommends it as a durable freestone. It dips rather confused- 

 ly, varying from 14° to 30° east by south, south-east, or even south-east by south. 

 Above it are beds of shale. It is evident that great disturbances have here taken 

 place, which are further manifested as we approach the highroad leading to Loanhead, 

 where the sandstone which is exposed betrays much irregularity of position. Its 

 general angle of inclination is about 22°, or upwards, to the south-east. It is sur- 

 mounted by bituminous shale. 



Between Straton quarry and Fountain-well, near Loanhead, a distance of about 

 five furlongs, we continue our section at right angles to the line of direction observed 

 by the strata. With the exception of two or three spots of ground, where I found 

 beds of slaty sandstone or of shale crop out, the ground is much covered. But my 

 knowledge of this interval of distance was rendered perfectly satisfactory by the in- 

 formation communicated to me by Mr Ross of Loanhead, the intelligent greve of 

 Sir George Clerk of Penicuik, Bart. Mr Ross has made himself well acquainted with 

 the different strata of his neighbourhood ; and from him I acquired the knowledge, 

 that the covered ground between Straton and Fountain- well had been very carefully 

 explored, in the endeavour to find out if there were any outcrops of coal. The re- 

 sult of the examination was, that the interval of space between Straton quarry and 

 Fountain-well, near Loanhead, consisted of alternations of freestone and coal blaes, 

 (sandstone and bituminous shale,) with ironstone bands, which also contained very 

 thin and unworkable seams of coal. From this remark, however, I except a thicker 

 seam of coal, which is said to lie immediately below the Fountain-well limestone. 



As far as the few visible outcrops of this space of ground enabled me to judge, I 

 was led to infer that the dip of the strata, in ascending from the lower to the higher 

 beds, was gradually increasing. For instance, the deep-seated bed of the Burdie- 

 house limestone inclines from 23° to 25° to the south-east ; but, in the strata higher 

 up in the system, the inclination had increased to not less than 30° or 40°, or even 

 more. 



The highest bed of the series of strata, intermediate to the limestone of Burdie- 

 house and the limestone of Fountain-well, is the seam of coal formerly alluded to, 

 known by the name of the " North-green seam." It is of the thickness of 4|- feet ; 

 but, having been very early wrought out, its outcrop is no longer visible. It is af- 

 firmed to lie immediately below the limestone of Fountain-well. 



A bed of coal holding this position is not unknown in other vicinities. Mr Wil- 

 liams has remarked a seam which occurs in this position, near to the foot of the Pent- 

 lands, and I have myself observed another similar one in the vicinity of Clerkington. 



