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COAL-FIELD OF CLACKMANNANSHIRE. 131 



for the old red sandstone ; and as it is generally ad- 

 mitted, that no beds of coal of any value have ever 

 been found in or under the old red sandstone, many 

 mineralogists have considered the valuable beds of 

 coal found under red sandstone in Clackmannan- 

 shire as an anomaly in this particular. This mis- 

 take originates from not examining the structure of 

 the red sandstone of this coal-field minutely. When 

 viewed at a distance as in the mass or in a building, 

 it has a blush-colour, very different from the old 

 red sandstone, and is now termed the Blush-colour- 

 ed Sandstone. On examining it minutely, the 

 quartz particles are of a white-colour ; and the red 

 colour is produced by a soft red oxyd of iron, dis- 

 seminated through the texture of the stone, which 

 easily rubs off, and soils the clothes and fingers. 

 The character of this stone is so well known by 

 those acquainted with the collieries of Scotland, that 

 in many districts it is considered as the index to 

 the coal-fields, as at Glasgow. The appearance of 

 this stone led Dr Mackenzie, a member of this so- 

 ciety, into a misconception, in his Essay on the Mi- 

 neralogy of the Ochill Mountains, inserted in the 

 Wernerian Transactions; for the Doctor having exa- 

 mined the old red sandstone in the eastern part of 

 the Ochill Mountains, concluded, that the red sand- 

 stone which is so distinctly seen at Harvieston, to 

 the east of the Westertown Glen, lying above a 

 thick bed of coal, and dipping towards the Ochills, 



