CHAPTEE XXI 
VOLCANOES OF THE LOWER OLD RED SANDSTONE OF THE CHEVIOT HILLS, 
LORNE, “ LAKE ORCADIE ” AND KILLAENEY 
THE CHEVIOT AND BERWICKSHIRE DISTRICT 
In the soutli-east of Scotland, and extending thence into the north of 
England, the remains of several distinct volcanic centres of the Lower Old 
Eed Sandstone may still he recognized. Of these the largest and most 
interesting forms the mass of the Cheviot Hills ; a second has been partially 
dissected by the sea along the coast south from St. Abb’s Head ; while 
possibly relics of others may suiwive in detached bosses of eruptive rock 
which rise tlirough the Silurian formations of Berwickshire. The water- 
basin in which these volcanic groups were active Avas named by me “ Lake 
Cheviot,”^ to distinguish it from the other basins of tlie same geological 
period (Map I.). 
The volcanic rocks of the Cheviot Hills, though their limits have been 
reduced by faults, uneonformable overlap of younger formations and severe 
denudation, still cover about 230 square miles of ground, and rise to 
a height of 2676 feet above the sea. As they have been mapped in detail 
by the Geological Survey, both on the English and the Scottish sides of the 
Border, their structure is now known.^ No good horizontal section, however, 
has yet been constructed to show this structure — a deficiency which, it is 
hoped, may before long be supplied. 
' Trans. Iloy. Soc. Edin. xxviii. (1878), p. 354. 
- The Geology of tlie Cheviot Hills is comprised in Sheets 108 N.E., 109 N.W., and 110 S.W. 
of the Geological Survey of England and AValcs, and in Sheets 17, 18 and 26 of the Geological 
Survey of Scotlanil. For descriptive accounts the Jlemoirs to .some of these Sheets may be con- 
sulted, p.articularly “Geology of tho Cheviot Hilhs" (English side), by C. T. Clough (.¥c?n. Geol. 
Surv. 1888); “Geology of Otterburn and Elsdon,” by H. Miller and C. T. Clough (dfoji. Gcol. 
Stirv. 1887); “Geology of Part of Northumberland between Wooler and Coldstream,” by W. 
Gnnn and C. T. Clough, with Pctrographical Notes by W. W. Watts {Mem. Gcol. Siirr. 1895). 
Other descriptions have been published by Professor James Gcikie, Good Words, vol. xvii. (1876), 
reprinted in Frayimnts of Earth-lore (1893), and by Prof. Lobour, OutHnes of the Geology of 
NorOiumherland, 2ud edit. 1886. For the peti'ograjihy of the rocks consult Mr. J. J. H. Teall, 
Geol. Mag. 1883, pp. 100, 145, 252, 344 ; 1884, p. 226 ; 1885, p. 106 ; Proc. Geol. Assoc, ix. (1886) 
p. 575 ; and his EriHsh Petrography, 1888 ; Dr. J. Petersen, Mikroskopiseke imd chemische Unter- 
siichimgcn am EnstalUporphyril am den Cheviot Hills, Inaugural Dissertation, Kiel, 1884. 
