130 COAL-FIELD OF CLACKMANNANSHIRE. 



roidal masses of clay ironstone, with a mixture of 

 lime* These contain beautiful impressions of bivalve 

 shells. Under these strata, a thick bed of red sand- 

 stone exists ; but to what part of the series of the 

 the coal strata this red sandstone belongs, I have not 

 yet been able to determine with accuracy. I have 

 no doubt, that there are thin beds of coal alternat- 

 ing with these strata, the same as observed in the 

 strata under the high greenstone cliffs of Stirling 

 Castle, which are also within the range of the Scotch 

 coal-field, which coal is of the species Glance coal. 



In the section of the strata in the Westertown 

 Glen of Tillicoultry, the junction of the coal forma- 

 tion with the Ochill Mountains is beautifully dis- 

 played ; and there a bed of greenstone rock, about 

 100 feet thick, is either the lowest bed of the coal 

 formation, or is the first of the Ochill Mountain 

 rocks. This Westertown Glen, in particular, and 

 all the glens in the vicinity, exhibit the most beau- 

 tiful and distinct sections of the coal formation, and 

 its junction with the mountain rocks, interesting in 

 the highest degree to the geologist. 



With regard to the south coal-field next to the 

 river Forth, the strata there have a contrary dip to 

 the south in place of the north ; and form the strata 

 into the mantle shape, or what is commonly termed 

 a Saddle. 



One particular feature in this coal-field, is the 

 abundance of red-coloured sandstone, many fathoms 

 in thickness, which has been frequently mistaken 



