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 complete suite 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 
