41S 



Remarks on the 



[J UN's. 



I have learnt from Dr. Macculloch that it occurs in great abun- 

 dance in the north. 



I am inclined to consider that it occupies a large proportion 

 of Forfarshire; and if I be correct in an observation made oti 

 the banks of Loch Katrine several years ago^ the transition rock^ 

 extend in that direction. I have likewise found traces of them 

 on the right bank of the Clyde, near Dalnotter Hill, in Dun- 

 bartonshire. But the transition country we are best acquainted 

 with is that of the south of Scotland^ which stretches entirely 

 across the island. 



On the one side it begins near the boundary between East 

 Lothian and Berwickshire, and continues along the coast to a 

 little beyond the river Tweed. Extending a line from the first 

 to a point on the west coast, between Girvan and Ballantrae ; 

 and from the second, another which shall pass by Langholm to 

 a point between Annan and Carlisle, we shall find nearly the 

 Vi/hole of the intermediate space to be transition, excepting 

 where granite comes in, and some partial deposites of later 

 strata, which occupy the lower parts of the valleys of Nith^ 

 Annan, &c. The mountainous district of Cumberland, West- 

 moreland, and the north of Lancashire, which is divided from 

 the transition of the south of Scotland only by a small propor- 

 tion of parallel strata/'^ belongs to the same, at least we know 

 of none other with which it can be classed, although it contains 

 a variety of rocks, which cannot be referred to any in the series 

 of Werner. Adjoining to this, in the western part of Yorkshire, 

 the same rocks occur : it is on these that the limestone of Ingle- 

 borough and Whernside rests. To this succeeds the extensive 

 district of parallel strata, including the coal-fields of Warrington 

 and W^igan, and the great alluvial deposite of Cheshire. These 

 bring us to the neighbourhood of the Welch mountains, which 

 t believe are all of the same nature, some specimens having 

 been given me by a member of this Society, taken from the 

 summit of Snowden. Graywacke, according to Mr. Aikin, 

 makes its appearance at Church Stretton, in Shropshire ; f and 

 near Hay, on the border of Hereford, I observed it myself. 



A great part of Somerset, and, finally, the whole of Devon 

 and Cornwall, again excepting the granite, and a small portion 

 of serpentine, and some other rocks, are all composed of transi- 

 tion strata. Thus, by extending a line almost due south, fronx 

 Berwick to the English Channel, we shall find a large proportion 



* This term has been applied to distinguisb the sandstone strata, and in that 

 sense I now use it ; it is objectionable, however; for all stratified rocks present 

 the phenomena of parallelism, consequently, without qualification, this term 

 aifords no distinction. 



t Geological Transactions, vol. i.p. 212. 



