183 
NOTES ON THE VOLCANIC ROCKS OF THE CHEVIOT HILLS. 
BY HERBERT KYNASTON, B.A., F.G.S., OF THE GEOLOGICAL SURVEY 
OF SCOTLAND. 
{Prepared for the Meetiiig and Field Excursion, at Wooler, 
July 13th to July 17th, 1900.) 
Literature. 
Geol. Mag., 1883, pp. 100, 145, 252, 344. 
Do. 1885, pp. 106-121. 
Papers by Mr. J. J. H. Teall on Specimens 
of Andesite, Porphyrite, Quartz-felsite, and 
Granite. 
Mem. Geol. Survey (Sheet 108 N.E,). The Cheviot Hills 
(English side), by C. T. Clough. 
Sir Arch. Geikie, Ancient Volcanoes of Great Britain, 
Vol. I., pp. 337, 338. 
Trans. Edin. Geol. Soc, Vol. VII., pp. 390-415. Contri- 
butions to the Petrology of the Cheviot Hills, by 
H. Kynaston. 
The volcanic district of the Cheviot Hills consists essentially 
of a central core or plug of granite, occupying an area of about 
12 square miles, surrounded by a more extensive area of ande- 
sitic lava-flows. Both the granite and the lava-flows are traversed 
by numerous sills and dykes of porphyrite and quartz-felsite. The 
lavas are of Lower Old Red Sandstone age, and rest uncon- 
formably upon the Silurian, and are overlain by Carboniferous. 
We will describe briefly the principal varieties of igneous rocks 
met with in the district. 
