28 The Rev. S. Haughton on the Chemical Composition of 



Table IV.— Isolated Granites. 



No. 1. Cushbawn. — Specific gravityj 2'671. A fiiie-grained 

 granite, containing hornblende in addition to mica. 

 Besides the constituents given in the table, the specimen 

 examined by me contained 1*34! per cent, of carbonate of 

 lime. 



No. 2. Croghan Kinshela. — Specific gravity, 2*629. This 

 granite is composed of quartz, felspar and chlorite ; the 

 specimen examined appeared to be composed exclusively 

 of quartz and felspar. From the great quantity of soda, 

 I infer that the felspar of Croghan Kinshela is probably 

 albite. On the northern slope of this mountain are situ- 

 ated the old gold streams of Wicklow. 



No. 3. Ballymoty. — Specific gravity, 2-659. A very fine- 

 grained granite, but containing distinctly felspar, quartz 

 and black mica. 



No. 4. Balhinamuddagh. — Specific gravity, 2-670. A coarse- 

 grained granite, with large plates of black mica. 



Applying to the preceding granites the method of calculation 

 already employed, we find, excluding the granite from Croghan 

 Kinshela, which contains chlorite in place of mica, — 



Table V. — Atoms of Granitic Minerals, 



From the foregoing Table, it appears that the granite of Cush- 

 bawn cannot be considered as a ternary compound of quartz, 

 felspar and margarodite, and in fact it contains a sensible quan- 



