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XLV. 



ON THE MESOLITE (GALACTITE) OF KENBANE HEAD, 

 CO. ANTRIM. By J. SHEARSON HYLAND, Ph.D., M.A., 

 of the Geological Survey of Ireland. 



[Read February 10, 1890.] 



The basaltic rocks of the North of Ireland have long been noted 

 for their richness in zeolites, and the publications of Jameson, 1 

 Giesecke, 2 Thomson, 3 Tamnau, 4 Portlock and others, 5 testify to the 

 interest these minerals excited amongst the collectors of that time. 

 To Thomson's enthusiasm for mineralogical investigations we owe 

 most of our present knowledge of their chemical composition. The 

 researches of this chemist have enriched our nomenclature with 

 such names as Lehuntite, Harringtonite, Erinite, 6 &c. ; but, as the 

 right of some of these minerals to be regarded as distinct species 

 is open to considerable doubt, it seems desirable to re-determine 

 their chemical characters. Since Thomson's time little, if any, 

 inquiry has been made into the subject. 



Along the cliff near Kenbane Head, about two miles W. of 

 Ballycastle, Co. Antrim, the decomposed basalt is seamed with 

 veins of white needle-like zeolite. At times it is associated with 

 analcime, showing the form 202 (211). Analcime is not very 

 common in Ireland ; but its occurrence " near Fairhead " is 

 already recorded by Giesecke. 7 



1 A System of Mineralogy, 3rd edn., 3 vols. : Edin. 1820. 



2 A Descriptive Catalogue of a New Collection of Minerals in the Museum of the 

 Royal Dublin Society, to which is added an Irish Mineralogy. Dublin : 1832. 



3 Outlines of Mineralogy, Geology, and Mineral Analysis. 2 vols., London : 183G. 



4 Monographie des Chabasits. Neues Jahrbuch: 1836, p. 633. 



5 Report on the Geology of the County of Londonderry, and of parts of Tyrone and 

 Fermanagh. Dublin: 1843. Also, Manual of the Mineralogy of Great Britain and 

 Ireland, by Greg and Lettsom. London : 1858. 



6 This is not to be confounded with Haidinger's Erinite, which is Cu 3 (As0 4 ) 2 

 -f 2Cu(OH)'~, and occurs at Limerick. 



7 I. c, p. 215. 



