COAL-FIELD OF CLACKMANNANSHIRE. 135 



the coals of this extensive coal-field are cubical and 

 splint coal; no caking coals or glance coals have 

 been yet found amongst them. 



With regard to the Ochill Mountains, the high- 

 est of these is Bencleuch, about 2400 feet above the 

 level of the sea. It is immediately north, and ad- 

 joining the Wood-hill represented in the section, 

 which is about 1800 feet in height above the same 

 level. They are composed of rocks, which, accord- 

 ing to the celebrated Werner, belong to the Transi- 

 tion class. The first of these, upon which the coal 

 strata rest, is Greenstone, as before mentioned, about 

 100 feet thick ; the upper part of which is composed 

 of large globular concretions, which exfoliate very 

 much. The lower part of it is strong compact 

 greenstone, with the fissures as usual at right an- 

 gles to the bed on which it rests. From the vertical 

 position of this bed of greenstone, and the fissures 

 being very distinct, one might be led to conclude 

 erroneously, that it was a bed of regularly stratified 

 greenstone. This greenstone contains many minute 

 particles of pyrites, which are evidently the cause of 

 its exfoliation. The next bed in succession, is Clink- 

 stone, of a darkish green colour, about 140 feet in 

 thickness. Next to this, is a very thick bed of 

 Sienite, in which are found narrow veins, containing 

 fine iron ore, or haematites, exactly similar to the 

 Cumberland ore, having a beautiful radiated struc- 

 ture. Below the sienite, are numerous thick alter- 

 nating beds of Clinkstone-Porphyry, and Sienite. 



