114 REMARKS ON THE 



The only limestones of this class that I know of, are three : 

 First, that of Rae Quarry, near Crook in Peeblesshire, where 

 it is interstratified with grauwacke, and contains abundance of 

 shells. The second is that of Cumberland, on the lakes of 

 Windermere and Coniston, which also contains organised bo- 

 dies. The third is the Plymouth limestone, which, according 

 to the account of Professor Playfair, corroborated by Dr Ber- 

 ger, is also transition-limestone ; and in it Mr Playfair 

 states, that he found a petrified shell *. I have not my- 

 self visited the spot, but it is of consequence to observe, 

 that the limestones of all these different districts exhibit traces 

 of organic remains. The other transition-rocks, are Trap and 

 Flinty-slate f; but I have had no opportunity of observing either 

 of them in their natural position. Such, according to Werner, 

 is the extent of the Transition series ; but it does not compre- 

 hend all the rocks which occur in some of the transition dis- 

 tricts, particularly that of Cumberland, although, with little ex- 

 ception, it is adapted to the south of Scotland, in a very remark- 

 able manner. 



I may now notice the extent of country occupied by rocks 

 of this description ; but such is our limited acquaintance even 

 with our own island, that it can be done only in an imperfect 

 manner. We know too little of the north of Scotland, to be 

 able to say, what rocks occur beyond the Moray Frith ; but it 

 is by no means improbable, that when these regions have been 

 more fully examined, the transition series will be found among 

 them. Indeed I have learnt from Dr Maccullocii, that it oc- 

 curs in great abundance in the north. 



* Illustrations of the Huttonian Theory, p. 165. 



f I suspect both these abound in the mountains of Cumberland, from speci- 

 mens I have picked up among the loose fragments. 



