14 Proceedings of the Royal Physical Society. 



They have now completed the mapping of the northern 

 counties of England, and have traced the boundary lines 

 northwards to the Border counties. The results of their 

 work tend to show that the Calciferous Sandstone Series of 

 Scotland represent the shore deposits of the sea in which the 

 Carboniferous Limestone of England was laid down, while 

 the Scottish Carboniferous Limestone Series is the equivalent 

 of part of the English Yoredale rocks — the uppermost divi- 

 sion of the Carboniferous Limestone. 



The physical evidence supplied by the Lower Carboniferous 

 rocks of the central and border counties shows that they were 

 laid down on a very uneven platform, which must have sub- 

 sided so slowly as to allow portions of the Silurian tableland 

 to remain above water till the commencement of the deposi- 

 tion of the Coal Measures. Hence we naturally find con- 

 siderable variation in the character of the deposits, and 

 especially of the lowest members of the series. Confining 

 our attention for the present to the Cement-stone group, 

 there seems to have been three separate areas of deposit : — 

 (1.) the Border territory, extending along the border counties 

 of England and Scotland, by the shores of the Solway, to the 

 north of Ireland ; (2.) the Lothian area, comprising the 

 greater part of the Lothians, a portion of Fife, and the eastern 

 districts of Lanarkshire ; (3.) the western area, including the 

 remainder of the Carboniferous territory south of the High- 

 land border. The Silurian tableland formed the dividing 

 ridge between the Lothian and Border regions of deposit, 

 while the Lothian and western areas were separated from 

 each other by a barrier of Upper Silurian and Old Bed Sand- 

 stone rocks, now exposed in the neighbourhood of Lanark, 

 where it is overlaid by the basement beds of the Carboni- 

 ferous Limestone. The northward extension of this barrier 

 is buried underneath the higher members of the Carboniferous 

 Limestone and the Coal Measures. The volcanic rocks of the 

 Ochils formed the northern termination of this ancient ridge. 



In the Border area, where the Upper Old Bed Sandstone 

 is absent, the Cement-stone group attains a great thickness. 

 The local base consists of a remanie conglomerate, composed 

 of the harder portions of the underlying rocks, overlain by a 



