in the Neighbourhood of Edinburgh. 239 



to the Burdiehouse system, by the second line of fault described, 

 which may be observed in the channel of Bilston Burn ; and from 

 the Stobhill system, by the third line of fault which with diffi- 

 culty is to be traced near the South Esk. 



On the east of the Hawthornden system, occurs that of Stob- 

 hill. A line of fracture, probably accompanied with a concealed 

 protrusion of trap, has thrown up a limestone of marine origin, 

 which forms the ridge of the Roman Mount, and from this anti- 

 clinal centre, superincumbent strata of sandstone, shale, and coal, 

 dip towards the surrounding low declivities. The system of 

 Stobhill has a westerly dip, amounting in some places to 30°. It 

 is continuous with the coal-measure of Brians, which enumerates 

 twenty seams of coal or more. 



To the west of the Hawthornden system, may be observed 

 the most completesuite of carboniferous strata of which Mid-Lo- 

 thian has to boast ; namely, the conjoint systems of Gracemount 

 and Burdiehouse. 



Immediately to the east of the Pentland trap, beds of sand- 

 stone are to be found, which I have named the Gracemount sys- 

 tem, from a quarry recently opened there, where the strata in 

 their nearly vertical position may be observed. They belong, as 

 I conceive, to deeper seated beds, which have been thrown up 

 during an early eruption of the Pentlands. They are separated 

 from the Burdiehouse system by the first line of fault enume- 

 rated. 



The Burdiehouse system comprises a series of sandstones, 

 shales, limestones, and coal, among which the Burdiehouse lime- 

 stone appears in a very inferior position. The system is separat- 

 ed from that of Gracemount by the first line of fault described. 

 Near this line of fissure the strata of the Burdiehouse system dip 

 to the south-east at about 23° to 25° ; but, as we approach to- 

 wards the Hawthornden system, the dip may be found to gra- 

 dually increase, until it attains, near the second described line of 

 fault observable at Bilston Burn, so great a dip as 56°, or even 

 more. It is difficult to explain this circumstance without taking 



