166 Proceedings of the Royal Irish Academy. 



augite, felspar, and olivine may be seen to penetrate it in such, a way 

 as to leave no doubt that the Carnmoney mineral has been deposited in 

 those spaces.^ 



Under these circumstances I consider it to be an original (but se- 

 condary) mineral, and believe it to be a new variety of the chloritie 

 group, and a "well-marked one. I therefore propose to give this Irish 

 variety a distinguishing name. 



ITacculloch, in his description of the mineral chlorophseite, apolo- 

 gises for giving it a new name, saying that though it may afterwards 

 turn out a variety only, its characteristics are strongly marked ; and 

 that the best chance of its obtaining future investigation will be de- 

 rived by giving it a conspicuous place in the list of minerals. On the 

 same grounds I venture to name the present mineral as a new species. 

 Since distinctness of colour and hardness may vary in different speci- 

 mens, and therefore mislead — and there is no earthly use in commemo- 

 rating a single locality when the mineral may hereafter be found in 

 hundreds of places — I submit that the best name would be that of an 

 individual. I propose to name this species or variety Hullite, after Pro- 

 fessor Hull ; first because it has been analysed and described during 

 his directorate of the Geological Survey of Ireland ; and last, but not 

 least, in commemoration of the valuable work he has done in the elu- 

 cidation of the microscopic mineralogy of the rocks of Ireland, more 

 especially that of the basalts. 



In order to set at rest any question as to the mineral being an 

 alteration product, Professor Hull, at my request, had some slices of the 

 rock made, and the microscopic examination of them fully bears out 

 my previous remarks, viz., that the mineral is perfectly distinct from, 

 and does not merge into any part of, the basalt. 



Paet II. — On the Miceoscopical Steijcttir'e op the Olivine Basaxt 

 o? Cahkhoi^et Hill, Co. A^fTKiir. By Professor E. Hull, M, A., 

 E. E. S. 



The rock occurs as a dark crystalline mass, with columnar struc- 

 ture, filling the neck of an old volcanic vent of the Miocene age. {See 

 Geology of the Country around Antrim, Mem. Geol. Sicrvey, Sheet 21, 

 p. 30). "With the lens it is seen to consist of black glistering crystals 

 of augite, set in a paste consisting of a light-coloured waxy felspar 

 (plagioclase), and large and small grains of an opaque, black, dense 

 mineral, with smooth, somewhat conchoidal, fracture, and brown 

 streak. This unknown mineral is that to which Mr. Hardman has 

 applied the name "Hullite," and the chemical composition of which he 

 has determined. The olivine, though seen to be remarkably abundant 



^ See Prof. Hull's remarks furtlier on. 



