CHAP. XXXII 
PERMIAN VOLCANOES OF DEVONSHIRE 
95 
the series to recognized Permian deposits in the centre of England and to 
parts of the typical Eothliegende of Germany. I need only refer to the 
strongly expressed views of Murchison, in which, as he stated in his 
Siluria, he “ entirely agreed with Conyheare and Buckland, who, after a 
journey in Germany in 1816, distinctly identified the Heavytree con- 
glomerate, near Exeter, with the Eothliegende of the Germans.” 1 In the 
absence of any fossil evidence, we have only lithological characters and 
sequence to guide .us, and though the known facts hardly warrant a very 
positive opinion, my inclination is to regard these red Devonshire breccias 
as probably Permian, and to follow Murchison in looking upon their 
associated igneous masses as furnishing additional reason for assigning them 
to that particular geological platform. 2 
No proper account has yet been written of the volcanic group which I 
now propose to describe. 3 De la Beche was, I think, the first to recognize 
the true volcanic nature of the rocks and their contemporaneous inter- 
stratification in the red sandstone series. 4 As traced by him on the 
Geological Survey maps, these rocks lie at or near the base of the red 
sedimentary deposits, resting sometimes directly on the Culm - measures, 
sometimes on an intervening layer of red strata. He found them in three 
separate districts in the neighbourhood of Exeter, the most northerly lying 
near Tiverton, the central extending from Kellerton for a few miles up the 
Yeo Valley, beyond Crediton, and the third stretching from the City of 
Exeter to Pen Hill, about five miles to the south-west. He recognized the 
amygdaloids as slaggy lavas, and saw that the volcanic breccias and tuffs 
are interleaved with the sandstones. With regard to the probable vents 
from which these materials were ejected, lie thought that the chief centre of 
activity lay at Kellerton Park, while in other localities he believed the 
bosses of igneous rock “ to descend in mass downwards, as if filling up some 
crater or fissure through which these rocks had been vomited.” 5 He speaks 
also of “ quartziferous porphyries ” occurring among them, a statement 
which, if petrographically accurate, would suggest the uprise of a later more 
acid lava in some of the vents. 
More recently the ground has been revised by Mr. W. A. E. Ussher of the 
Geological Survey, who has ascertained that the volcanic rocks appear in 
1 Siluria, 4tli edit. (1887), p. 333. See also Berger, Trans. Geol. Soc. vol. i. (1811), pp. 
88-102 ; Conyheare and Phillips, Geology of England and Wales, p. 313, footnote; De la Beche, 
Report on the Geology of Cornwall, Devon and West Somerset (1839), chap. vii. p. 193. Messrs. 
Hull and Irving (Quart. Journ. Geol. Soc. vol. xlviii. 1892, pp. 80, 88) have more recently 
discussed the subject, and follow the view of Murchison. 
2 Murchison cogently argued that as no signs of volcanic activity were known in the Trias, but 
were abundant in the Permian system, the Devonshire rocks might be regarded as appertaining to 
the older series, op. cit. Triassic volcanic rocks, however, are now well known on the Continent. 
3 An outline of some of their characters will he found in a paper by Mr. W. Yicary in Trans. 
Devonshire Assoc. 1805, vol. i. part iv. p. 43. 
4 See liis “ Report ” cited in the note above. De la Beelie quotes J. J. Conyheare as pointing out 
the intimate connection of these igneous and stratified rocks (Annals of Philosophy, 2nd series, vol. 
ii. (1821) p. 165) ; hut this author wrote at the time of the Plutonist and X eptunist controversy, 
and does not commit himself to any distinct expression of opinion on the subject. 
6 Report, p. 201. 
