CHAPTER XIV. 



OLD RED SYSTEM. 



I. Conglomerate and Sandstone. — 2. Comstone and Marl. — 3. Tilestone. 



THE rocks known to English geologists under the name of the Old Red Sandstone, 

 consist of various strata of conglomerate, sandstone, marl, limestone, and tilestone, the 

 youngest beds of which dip conformably beneath the carboniferous deposits, whilst the 

 oldest repose upon and pass into certain grey-coloured rocks. These grey-coloured 

 rocks form the upper part of the Silurian System. (See coloured section upon the Map, 

 also PI. 31. figs. 1 to 4, and wood-cut p. 171.) 



Being convinced that the Old Red Sandstone is of greater magnitude than any of the 

 overlying groups, I venture for the first time in the annals of British geology to apply- 

 to it the term system, in order to convey a just conception of its importance in the 

 natural succession of rocks, and also to show, that as the carboniferous system, in 

 which previous writers have merged it 1 , (but from which it is completely distinguishable, 



1 See even the very recent vocabulary used in the Bridgewater Treatise by Dr. Buckland, in which the Old 

 Red Sandstone is made a subordinate part of the carboniferous system, the same divisions being there retained 

 which were first put forth by Mr. Conybeare. Mr. Lyell, however, has in great measure adopted the classifi- 

 cation here proposed. Professor Sedgwick, and myself, have examined these rocks over a wider area, perhaps, 

 than most English geologists, and he coincides in the necessity of separating the Old Red Sandstone from the 

 overlying and subjacent systems. (See memoir by Professor Sedgwick and myself on the Old Red Sandstone of 

 the Highlands of Scotland. Geol. Trans, vol. iii. and subsequent memoirs by Professor Sedgwick, Geol. Trans, 

 vol. iv.) The Norwegian rocks should be examined in detail by some competent observer to decide how far 



