[ 511 ] 



XXXV. 



THE VAEIOLITE OF ANNALONG, CO. DOWN. By PEO- 

 FESSOK GEENVILLE A. J. COLE, F.G.S. (Plate XXI.) 



[Read Fekruary 17, 1892. J 



Among the specimens of igneous rocks from Ireland arranged 

 by the officers of the Greological Survey in the Museum of the 

 Department of Science and Art, Dublin, is one which attracted my 

 attention from its resemblance to the historic variolite of Mont 

 Oenevre^ The old label affixed to the specimen reads, " Yariolite 

 from a dyke. Kilkeel, E. Coast of Mourne. Co. Down." I 

 am informed that the rock was collected when the Survey was 

 under the direction of Major- General J. E. Portlock; and a 

 reference to the paper by Major S. Patrickson on the " Dykes 

 appearing on the shore which skirts the Mourne Mountains "^ 

 shows that in former years the term variolite was familiar to 

 workers on the dyke-rocks of this country. Whether the variolites 

 mentioned by Major Patrickson are literally such, or in some 

 cases merely amygdaloids, as is suggested by his dyke numbered 

 39, must be left to future examination of the coast ; the more so as, 

 curiously enough, he omitted to notice the rock now under con- 

 sideration, which was probably covered by high water at the time. 

 It comes very near his number 51, " Analory " in his Paper being 

 clearly Annalong. 



Nor is this rock included among the " Spherulitic Rocks from 

 Co. Down " described by Dr. J. S. Hyland.^ Hence it became of 

 interest to rediscover the dyke from which Portlock' s specimen was 

 derived, and to examine this rare rock in detail, the discovery of 



^ For references to tlds Alpine type, see Cole and Gregory, " The Variolitie 

 Rocks of Mont Genevre," Quart. Journ. Geol. Soc, vol. xlvi. (1890), p. 295. 



2 Journ. Geol. Soc. Dublin, vol. i., p. 182 (1835). 



3 Proc. Roy. Dublin Soc, vol. vi. (X.S.), p. 420. 



