TRANSITION ROCKS- ] 5 



the deposits at present forming below the waters of the 

 ocean, could be looked upon in one wide extended plain, it 

 would be found that their mineral characters are so differ- 

 ent in different places, that little similarity could be traced 

 amongst them. That deposit which resulted from the ero- 

 sion of a granitic district, would present the characters of 

 various red sandstones ; that which was produced by the 

 comminution of quartz rock, would approach in character 

 to a white sandstone ; while the formations which were 

 formed from the disintegration of secondary or tertiary dis- 

 tricts, would consist of various alternations of sands, gravels 

 and clays. In all these supposed cases there is nothing si- 

 milar to that uniformity of mineral character which is con- 

 spicuous in older formations ; a fact which indicates that the 

 causes effecting these formations were very general, and that 

 similar circumstances existed over an immense portion, if 

 not over all the globe at one period. 



SECONDARY ROCKS. 



Having now noticed generally the transition rocks of the 

 Lothians, we shall next describe that series of Secondary 

 strata which forms almost the whole of the counties of Edin- 

 burgh, Haddington, and Linlithgow. The Secondary series 

 of the Lothians is not composed of one and the same rock, 

 but is, on the contrary, an example of a compound forma- 

 tion, inasmuch as it is an assemblage of red and white sand- 

 stones, variously coloured shales, and limestone, all of which 

 are so associated with each other, that their synchronism of 

 deposition is conspicuously evident. The white sandstone 

 group of the Lothians has, as we have before stated, al- 

 ways been considered as belonging to the Independent Coal 

 Formation. This series differs in several respects from the 

 coal-measures of England. It would certainly indicate a 



