146 



MINERALOGY OF ST ANDKEW's. 



field which occupies the river district of the Forth, 

 An overlying formation of Trap rocks, in the form 

 of conical hills, or irregular patches, covers the 

 rocks belonging to these two formations, and may 

 be observed to the south as well as to the north 

 of the Eden. The city of St Andrew's is si- 

 tuated on the north-eastern extremity of the dis- 

 trict occupied by the strata belonging to the inde- 

 pendent coal formation. The rocks which occur 

 in the neighbourhood of the city, present a few 

 circumstances in their history, which deserve to be 

 noticed. These I shall briefly detail. 



In conformity with the plan pursued by the 

 disciples of the celebrated Werner, I shall state 

 my observations on the rocks which are consider- 

 ed the oldest, and afterwards notice those which 

 appear to have been deposited at a more recent 

 period. The rocks, therefore, which fall to be 

 considered first, are such as belong to the Inde- 

 pendent Coal Formation. 



The strata in the vicinity of St Andrew's, pre- 

 serve no regular line of bearing. In a few in- 

 stances, they are horizontal, but in general they 

 present basin- shaped or saddle- shaped undulations ; 

 the strata at the margins of these bendings, in- 

 cline to the horizon at various angles. The 

 rocks are chiefly Sandstone, Coal, Slate-clay, and 

 Clay-ironstone. 



The individual beds are subject to great varia- 

 tion in depth. The beds of sandstone in particu- 



