302 The Philvsophlad Society of Gliinyoio. 



Boghead Gas Coal. — Average Thickness, 10 Inches. — In the posi- 

 tion of the ironstone last described, at Bathgate, occurs the famous 

 Boghead gas coal, or Torbanehill mineral. This coal resembles the or- 

 dinary varieties of Parrot coal in its physical character, but gives off 

 about 3,000 cubic feet more of gas, per ton of coal, than any other coal 

 known. The upper part of the seam is brown, and the lower part of a 

 black colour. When distilled at a low heat, it gives off from fifty to 

 seventy gallons of paraffin oil, per ton of coal. This oil is extensively 

 manufactm-ed near Bathgate, and in the United States of America, 

 whither this coal is exported in large quantities for this purpose. This 

 valuable seam does not exist over a large area. It extends as far 

 north as Colinshields, as far east as Bathgate, and as far south as Tor- 

 banehill, and on the west it has not been discovered beyond Armadale. 

 In thickness it is very irregular, varying from one inch to twenty, and 

 the area containing it is much troubled and intersected by wants. Esti- 

 mated area still to work, 400 acres. 



About seventy-seven fathoms under the Slaty band, and at about 280 

 fathoms down in the general section, there occurs the Roman cement 

 seen at Glenboig brick- works, situated on the side of the Monkland and 

 Kirkintilloch Railway, about 2J miles from Coatbridge. It is about 

 twelve inches in thickness and of excellent quality. About three 

 fathoms farther, is the valuable fire clay used at these works, ranging 

 in thickness from eight to ten feet. At 328 fathoms in the general 

 section is the first or Caulm limestone of Garnkirk, Bedlay, Croftfoot, 

 Hoodie's burn, and Castlecarry. This seam is about 6J feet thick, and 

 divided in the centre by about four inches of hard shale. In quality 

 it is very good, containing rather more than forty per cent of lime. It 

 is extensively worked for the supply of the iron-works in the neighbour- 

 hood of Coatbridge, to which it is convej^ed by the Monkland and Kirk- 

 intilloch Railway. 



About two fathoms below the limestone there is a soft coal about 

 twenty inches in thickness, which was partially worked some years ago 

 at Garnkirk and Hogganfield, near Glasgow. At 412 fathoms in the 

 general section is the Bishopriggs limestone, seen in the Edinburgh 

 and Glasgow Railway tunnel. It corresponds in position with the lime- 

 stone of Cowglen and Jordanhill. 



At 443 fathoms in the general section we come to the first Fossil 

 coal ; and at 447 fathoms, to the Upper Fossil ironstone, which is the 

 first valuable seam under the Slaty band. 



Fossil Ieonstone. — At 447 Fathonis — Average Tkichiess, 12 

 Indies. — In what is generally known as the Fossil field there are five 

 seamSj^two of coal and throe of ironstone. 



