﻿INTRODUCTION. 



3 



The change to the state of matters found in Scotland begins already to appear in the 

 North of England, coal having been wrought in the Carboniferous Limestone series in 

 Northumberland, not far from Berwick. As the fossil ichthyology of the Scottish strata 

 is peculiarly interesting, a more special explanation of their arrangement and subdivisions, 

 which have been well wrought out by Professor Geikie 1 and the officers of the Scottish 

 Geological Survey, may be not unacceptable to southern readers. 



The Coal Measures of Scotland are essentially similar to those of England, to 

 which they are considered as being generally equivalent. Below the Coal Measures there 

 also occurs some thickness of reddish Sandstones known as " Rosslyn Sandstones " or 

 " Moor Rock/' which, both from their stratigraphical position and lithological characters, 

 may be considered as representing the Millstone Grit. 



The Carboniferous Limestone Series consists, however, of sandstones and shales, with 

 valuable seams of coal and ironstone, and contains, moreover, towards its upper and 

 lower limits, a few comparatively thin beds of marine limestone. In the latter, Mollusca, 

 Corals, and Polyzoa similar to those of the English Carboniferous Limestone occur, though 

 the catalogue of species is smaller, and, as regards the Brachiopoda at least, many exceed- 

 ingly common English and Irish species are either totally absent or very rare, while others 

 are distinguished by their very small size. 



Below the Carboniferous Limestone series, and especially developed on the eastern 

 side of Scotland, there exists a great thickness of strata, the " Calciferous Sandstone " 

 series of Maclaren. The upper portion of this series, known as the " Cement-stone 

 Group," consists of white and yellowish sandstones, with bituminous shales, beds of 

 limestone, including the well-known " Burdiehouse Limestone," cement-stones, and clay- 

 ironstones. It contains likewise a few seams of coal, but except in one instance, the 

 Houston coal, formerly wrought to the west of Edinburgh, these are too thin to be of 

 the smallest economic value ; the bituminous shales are, however, in many places wrought 

 for the manufacture of paraffin oil. This group is essentially estuarine in character, 

 although occasionally beds occur containing marine shells and Polyzoa, especially in the 

 east of Eifeshire. The lower portion of the Calciferous sandstone series, termed the 

 " Cornstone Group," consists of reddish sandstones and cornstones, almost entirely 

 destitute of fossils, and rests conformably on and passes into the Upper Old Red 

 Sandstone, to which latter formation the ichthyolite-bearing beds of Dura Den, Clash- 

 bennie, and Melrose must be referred, if the aspect of their contained fish-remains is to 

 be taken into account. 



The Carboniferous rocks of Scotland may be thus tabulated : 2 



Upper Red Sandstone Series. 



1 'Mem. Geol. Survey of Gt. Britain, Explanation to Sheet 32 (Scotland),' 1861. 



2 Copied from Mr. Bristow's ' Table of British Strata ' already quoted. 



