Frof. G. A. J. Cole— The Volcano of Tardree. 303 



amount of time to examining this special point, I could find none. 

 Be tliis as it may, it is the prettiest exhibition of the terminal 

 moraine of a small comb-glacier which I have seen in this or any- 

 other district, and it is well worth taking the somewhat uninteresting 

 walk which is necessary to reach it. 



IV. — The Volcano of Tardrke, County Antrim. 



By Grenville A. J. Cole, M.R.I. A., F.G.S., 

 Professor of Geology in the Eoyal College of Science for Ireland. 



I PROPOSE in the autumn of the present year to lay certain 

 detailed observations on the rhyolites of County Antrim before 

 the Royal Dublin Society; but meanwhile it may be of interest to 

 give some account of the mode of occurrence of these rocks in their 

 most central locality, the neighbourhood of Carnearney and Tardree. 



Mr. A. McHenry, F.G.S , some four years ago, while preparing 

 a series of specimens for exhibition in the Museum of Science and 

 Art, Dublin, called my attention to some of the little known varieties 

 of rhyolite from Sandy Braes; and I subsequently visited Hungary, 

 in order to become familiar with the typical highly silicated lava- 

 flows studied by Beudant, Von Richthofen, Judd, Szabo, and others. 

 Since then, in various visits to County Antrim, I became impressed 

 with the unique character of the Tardree volcano, as far as our 

 islands are concerned, and with the comparative neglect in which. 

 its beautiful products have been suffered to remain. 



The general characters of the district have been described in 

 the Memoirs of the Geological Survey of Ireland, and I shall hope 

 to discuss the question of the geological horizon of the rhyolites 

 when dealing with a wider area. It may be sufficient to remark 

 here that evidence as to the true relations of the rhyolites and the 

 basalts around Tardree is sadly wanting in the field. This has 

 been fairly recognised by those who have ventured to draw sections 

 across the district: and neither the intrusion of the Tardree mass as 

 a dome amid the older basalts, nor its burial by the later basalts, 

 can be regarded as absolutely proved. 



For some reason or other, the rhyolites of County Antrim have 

 been almost constantly styled " trachytes," although that name 

 has, for some thirty years, been restricted to another class of lavas. 

 Von Lasaulx's^ well-known examination of the Tardree rock is 

 to some extent responsible for this ; but he styled it a " quarz- 

 sanidintrachyf'in his descriptive paper, and a "quarzsanidinrhyolit" 

 in his more popular volume.-^ 



In the present state of nomenclature, the term " trachyte " can 

 no longer be used in connection with the Tardree volcano, nor, as 

 far as I am aware, with any post-Cretaceous rock in County Antrim. 



The main exposures of rhyolite in the Tardree area, as we go from 

 south to north, are met with as follows : — a cutting in a farm-road 



1 " PetrograpMsclie Skizzen aus Irlaud," Tschermak's Min. u. Petr. Mittlieilungen, 

 Bd. i (1878), jj. 418. 



2 "Aus Irland" (1878), p. 167. 



