TRIASSIC STRATA OF LANCASHIRE. 125 



the Esk immediately above Canobie Bridge. All our in- 

 vestigations in the Permian deposits lead us to expect great 

 changes and variations in the beds^ and to be prepared to 

 accept sections such as they are found, without predicting 

 what they should be in a new district. At some future 

 time there may be materials for placing them on a map 

 provisionally; but at present it is only in my power to 

 collect a few disjointed sections^ and preserve them as 

 guides for future workers. 



After the great change which has of late years been made 

 in the classification of the rocks formerly known as new 

 red sandstone found north of Manchester and Liverpool, 

 considerable portions of Trias having been transferred to 

 Permian, so that when we reach Carlisle little has been left 

 of the former rock, in my opinion probably less than it is 

 fairly entitled to. 



The arbitrary lines of division in the Carboniferous and 

 Permian formations, and the passage of the one into the 

 other, and the latter into Trias, although doubtless at some 

 places well-marked and distinct, and admitting of no doubt; 

 at other points, pass one into the other so gradually as to 

 render it hard to tell where one ends and the other begins, 

 when there are no organic remains to guide us, but simply 

 beds of red sandstone and red marl. 



All passage-beds require careful examination; and 

 when we have to trust to the composition of the beds 

 alone, without the aid of fossils, our views ought to be 

 expressed in anything but dogmatic language. Doubtless 

 we have much yet to learn of the highest Coal-Measures 

 and the lowest Permian beds, which is not rendered easier 

 by Mr. Scott^s discoveries of unconformable Coal-Measures 

 in the Coal Brookdale district, and Professor Ramsay and 

 Mr. Aveline^s description of apparently unconformable 

 Coal-Measures near Uotherham in Yorkshire. Added to 

 this, when we have a great thickness of unproductive Coal- 



