1858.] 



HAUGHTON GRANITES OF IRELAND. 



■ . ■ 



No. 5. Granite from Jonesborough Mountain, south of Newry, presenting a general 

 resemblance to that last described, with the exception that it contains no 

 white nests or small cavities. 



The paste is the same as the last (No. 4). The crystals of pinkish 

 felspar are more distinct and numerous than in the last rock. No quartz 

 is visible, except in connexion with some occasional and partially formed 

 cavities. Blackish-green stains and patches accompany the quartz, as in 

 No. 4. 



Table I. — Analyses of Potash-Granites. 





1. 2. 



3. 



4. 



5. 



Silica 



70-48 

 14-24 

 3-72 

 1-48 

 0-40 

 4-26 

 3-66 



1-59 



71-41 

 12-64 

 4-76 

 1-80 

 0-63 

 5-47 

 3-03 



7124 

 14-36 

 3-36 

 1-48 

 0-64 

 4-09 

 313 



1-50 



72-08 

 14-36 

 302 

 117 

 0-36 

 5-58 

 2-91 

 1-50 



71-00 

 1360 

 3-28 

 1-06 

 0-51 

 5-73 

 327 

 1-30 





Peroxide of iron . . . 



Magnesia 



Potash 



Soda 



Protoxide of iron . . 

 Loss by ignition ... 



Totals 



99-83 



99-74 



99-80 



100-98 



99-75 





The following Table shows the atomic quotients found from the 

 preceding analyses in the usual manner : — 



Table II.- 



-Atomic Quotients of Potash-Granites. 





1. 



2. 



3. 



4. 



5. 



Silioa 



1-566 

 0-274 

 0-046 

 0-053 

 0-020 

 0-090 

 0118 



1-586 

 0243 

 0-059 

 0-064 

 0-031 

 0-116 

 0-098 



1-583 

 0-276 

 0-042 

 0053 

 0032 

 0-087 

 0-101 



1-600 

 0-276 

 0-038 

 0-042 

 0-018 

 119 

 0-094 

 0-041 



1-577 

 0-261 

 0-041 

 0-038 

 0-025 

 0-122 

 0-105 

 0036 



Alumina 



Peroxide of iron... 



Magnesia 



Potash 





Protoxide of iron . 



Adding together the protoxides and peroxides in the preceding 

 Table, we obtain the following : — 



Table III. — Atomic Quotients of Silica, Peroxides, and Protoxides 



in Potash-Granites. 





1. 



2. 



3. 



4. 



5. 



Average. 



Silica 



1-566 

 0-320 

 0-281 



1-586 

 0-302 

 0-309 



1-583 

 0-318 

 0-273 



1-600 

 0314 

 0-314 



1-577 

 0-302 

 0-326 



1-582 

 0-311 

 0-301 



Peroxides ... 

 Protoxides... 



The preceding results show that these granites have a general 

 family resemblance, and that they should be grouped together. The 



x 2 



