78 CoLte—The Rhyolites of the County of Antrim ; with a Note on Bauxite. 
glassy products on the high plateau of Sandy Braes, though appreciated by Berger 
and localised by him on his map, were allowed to remain in ill-deserved 
obscurity.* For some reason, the whole of the Antrim rhyolites have been 
commonly styled “ trachytes,” in treatise after treatise, down to the present day, 
although the name ‘‘trachyte” has been restricted to another class of lavas for 
more than thirty years. 
Going from south-east to north-west, the exposures of rhyolite in Co. Antrim 
are as follows :— 
(i.) Templepatrick.—An ill-defined area about a mile-and-a-half long, including 
sections in the upper levels of a chalk-quarry. 
(ii.) Tardree area.—Exposures scattered over an area of about five by three 
miles, including two good quarries in Tardree Mountain, and excavations in the 
plateau of Sandy Braes. 
(iu1.) Hslerstown.—An obscure exposure. 
(iv.) Kirkinriola, north of Ballymena. A similarly obscure patch along the 
hollow of a stream. 
(v.) Ballycloughan ( Quarrytown).—There is a good quarry in this mass. 
(vi.) Cloughwater.—A small circular boss in the midst of a peat-bog, just west 
of the road from Ballymena to Cushendall, and one-and-a-half miles from 
Ballycloughan. 
The grouping of these exposures suggests that we are dealing with a series of 
small volcanoes opened along a line of fissure. A line drawn N. 27° W., through 
the centre of the dome of Tardree Mountain, passes through the east end of the 
Templepatrick quarry on the one hand, and across the Eslerstown area on the 
other; it leaves Kirkinriola a mile on the left, and Ballycloughan half-a-mile on 
the right, and bisects the little boss near Cloughwater school. ‘The direction of 
this hypothetical fissure corresponds well with that of so many of the basic dykes 
between Belfast and Carrickfergus, which can easily be traced out on the edge of 
the basalt plateau or on the shore. A similar north-north-westerly direction is 
common in the dykes as far north as the Giant’s Causeway, and as far south as 
the area of the Mournes.t The rhyolitic area between Dromore and Moira, 
Co. Down, lies well to the south of our particular line, and is probably more 
nearly connected with the granite masses of the Mourne Mountains.t 
It is probable, however, that many other centres of rhyolitic eruption he 
buried beneath the enormous outpouring of the Later Basalts. The conglomerates 
* Cf. Backstrom, Geol. Foren. i Stockholm Forhandl., Bd. xiii. (1891), p. 672. 
} This fact was observed by Berger, ‘‘On the Dykes of the North of Ireland,” Trans. Geol. Soc. 
London, vol. iii. (1816), p. 231. 
{ Memoir to Sheet 48, Geol. Survey of Ireland, pp. 10, 14, 16, and 37; Mem. to Sheet 36, p. 11. 
Also A. M‘Henry, ‘‘ On the Age of the Trachytic Rocks (Rhyolites) of Antrim,” Geol. Mag., 1895, p. 264. 
