360 MR J. D. FALCONER ON THE 
As convenient boundary-lines for the study of these hills, I have chosen as lower 
limit the final western outcrop of the Houston Coal from Drumeross to Champfleurie, and — 
thence a line drawn directly north to the shore of the Firth at Stacks, and as upper limit 
the outcrop of the Castlecary Limestone. The accompanying map represents on a 
reduced scale the 6-in. sheets ix. N.E., v. S.E., v. N.H, i. 8.E., 1. N.E. of Linlithgowshire, 
with the eastern halves of ix. N.W., v. S.W., v. N.W., i. S.W., i. N.W. of the same 
county. I have thought it unnecessary to continue the map to the south of the 
Bathgate Railway, beyond which the volcanic series rapidly runs out, while the country 
is so much covered with drift that little rock is visible. The geology below the 
Houston Coal and above the Castlecary Limestone is simply sketched in from the 
Survey sheets, and has not been personally verified in detail. 
The Houston Coal. 
The outcrop of the Houston Coal, crossed by numerous dip faults, has been well — 
proved from Deans to Drumcrosshall. Thence it strikes north by west tothe neighbour- 
hood of Blackeraig and West Binny, having been worked many years ago at both of 
these places. In the vicinity of Ochiltree Mill the outcrop is uncertain, the ground 
being much faulted and pierced by many intrusions. North of Peace Knowe, however, 
it reappears and strikes north by west to the Haugh Burn fault, by which it is shifted to 
the east beyond the limits of the present map. 
Between the Houston Coal and the first voleanic zone come the Houston shales 
and marls, with thin sandstones and occasional beds of ash and agglomerate. Good — 
sections are found in the Mains Burn and the Brox Burn and its tributaries. 
The First Volcanic Zone, or The Brox Burn Ash. 
This zone can be traced, with interruptions, from Drumcrosshall to the Haugh 
Burn. It consists throughout of stratified volcanic ash, varying much in texture and 
usually green in colour, but weathering yellow or brown at Chapelhill and Bankhead. 
Interbedded lava is nowhere found in this zone, although in places the compact ash 
weathers spheroidally, and presents a deceptive resemblance to a decomposing — 
crystalline igneous rock. Characteristic sections are found in the Brox Burn and its 
tributary to the south. On account of the absence of exposures, this zone cannot be — 
traced to the east of the Longmuir plantation. It reappears, however, on the same — 
horizon on the Riccarton road, immediately to the north. 
Between this ash and the second voleanic zone there appear some thinly bedded 
sandstones and shales, frequently ashy themselves, and interstratified with thin bands 
of ash. These are well seen in the Brox Burn and in a streamlet in the northern angle 
of the Longmuir plantation. 
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