to REV. A. lEVING ON THE RED ROCKS 



typical areas, we surely have an ample time-interval in that long 

 period, to which the Coal Measures testify, both by their thick- 

 ness and their genesis, for all the phenomena which have been 

 observed in connexion with the great Dartmoor upheaval and its 

 associated intrusive series. Fox aught we know, the time-interval 

 represented by the great unconformity at the base of the Permians 

 of the North of England may be only a portion of that time which 

 is represented in Devon. If this be so, there would seem to remain 

 no valid reason why the great Breccia-sandstone series of the Devon 

 E,ed Rocks should not be the true equivalents of the Lower Roth- 

 liegendes both in time and position in the sequence. It is even 

 possible that those j)ortions of them which filled up the fiords and 

 creeks of the more ancient ' Devonian ' land (e. g. at Babbacombe 

 Bay) may be even older than the Rothliegendes of some districts, 

 where it lies un conformably upon the Carboniferous coal-bearing 

 strata of Central Europe. 



On the other hand, it is by no means certain that the igneous 

 rocks associated with the breccias are older than they. Prof. Hull 

 has reminded me that "the contemporaneous volcanic rocks of the 

 breccias, so well described by De la Beche, are strong evidence of the 

 Permian age of these beds ; " and what I have seen in the field, 

 particularly in the Crediton Valley, referred to in my 1888 paper 

 (p. 159), points to the existence of true volcanic agglomerates 

 forming locally integral portions of the Breccia series. 



Contemporaneous volcanic action being unknown in the British 

 Trias, as it is altogether unknown in the Trias of Germany, such an 

 occurrence of volcanic activity in the Trias of Devon would be alto- 

 gether abnormal, except for the Alpine Trias, which presents a totally 

 different fades from the Trias of Germany and Britain. In the 

 absence of evidence derived fi^om fossil remains in the Breccia Series 

 of Devon, we have to rely mainly upon their strong lithological 

 resemblance to the Permian breccias of the Western Midland 

 counties and to the German Eothliegendes, upon which I laid par- 

 ticular stress in my former paper. 



The argument from this is seen to be considerably strengthened 

 by any evidence of contemporaneous volcanic activity in the Devon 

 series, which is paralleled by that met with in the Permians of 

 Ayrshire and of the country north of the Solway ; while in Germany 

 (in Thuringia, in Saxony, in the Harz region, in the region south of 

 the Hunsriick, in the Odenwald, in Silesia, in North-eastern Bo- 

 hemia, in the Black Porest, and in other localities) such igneous 

 rocks as quartz-porphyry, granite-porphyry, palatinite, porphyrite, 

 and melaphyre, with their associated tuffs and breccias, are so 

 commonly interstratified with, or intrusive in, the sedimentary 

 rocks of the Eothliegendes, as to present quite a special feature of 

 that formation, where the age of these sedimentary rocks is abund- 

 antly proved by their fossil remains. 



The association in places of manganese ores with the breccias of 

 Devon is another point of resemblance between them and the lloth- 

 liegendes, in which these ores are worked at several localities, 



