Mr Poulett Scrope on Volcanic Formations. 145 



stated above, indicate that the temperature of springs is af- 

 fected by the electric fluid. 



On the evening of the same 4th June, the hill-side spring 

 was 47°, but the aspect is westerly, and the sun had been, for 

 some hours, beating on the bank whence it issues. 



Note. — Stow is about 20 miles south from Edinburgh, and 

 is 500 feet above the level of the sea. 



Akt. XXXII. — Observations on the Volcanic Formations on 

 the Left Bank of the Rhine. By G. Poulett Scrope, Esq. 

 Communicated by the Author. 



1 he volcanic products which occur in the Prussian provin- 

 ces on the left bank of the Rhine, are scattered over a dis- 

 trict of no great extent, which may be described as bounded 

 on the south and east by the Moselle and Rhine, on the north 

 and west by a line passing from Bonn through Gemund, 

 Priim, and Bitburg, to Bemcastel on the Moselle. 



With the exception of the volcanic rocks, the surface of 

 this district is chiefly composed of transition slate, a part of 

 the great Rhine schist formation. In a few places this is par- 

 tially covered by some of the floetz strata, both sandstones and 

 limestones, to which I can scarcely venture to give a name. 

 The volcanic eruptions have forced their way with apparent 

 indifference, both on the points where the slate is covered by 

 these strata, and where it is exposed. The volcanic energy 

 has not confined itself to this district ; analogous formations 

 (though appearing in general to belong to an earlier epoch,) 

 occurring, as is well known, eastward of the Rhine, in the 

 Siebengebirge, the high Westerwald, the Vogelsgebirge, the 

 Rhongebirge, the Meisner, and the Habichtswald, which 

 form altogether a remarkable volcanized band, stretching from 

 west to east in a line parallel to the primitive axis of the Alps, 

 and removed about four degrees to the northward of it. The 

 volcanic country which I have at present to describe has been 

 generally separated by writers into two districts, from the \ r ol- 

 canic products being more thickly grouped together at its 

 western and eastern extremities. These divisions are, 1. The 

 VOL. v. NO. I. JULY 1826. K 



