202 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 20, 



Soda-Granites of the Newry District* 





No. 1. 



No. 2. 



Mean. 



Atoms. 



Silica 



64-60 

 14-64 

 6-04 

 316 

 2-80 

 3-15 

 402 

 113 



62-08 

 15-92 

 7-72 

 5-52 

 2-16 

 2-19 

 3-34 

 0-89 



63-34 

 15-28 



6-88 

 4-34 

 2-48 

 2-67 

 3-68 

 101 



1-377 



j 0-383 



0-455 



Alumina 



Peroxide of iron . . . 

 Lime 



Magnesia 



Potash 



Soda 



Loss by ignition . . . 





99-54 



99-82 



99-68 





No. 1. — Coarse-grained granite, from Newry Quarry, intersected by trap-dykes 

 and veins of fine-grained pink granite ; consists of quartz, white feldspar, passing 

 into pale pink, and black mica. 



Specific gravity = 2-695. 



No. 2. — Coarse-grained granite, from GoraghWood Station ; composed of quartz, 

 white feldspar, and black mica. 

 Specific gravity =2-731. 



A comparison of these results with the granites of the third 

 isolated group of Leinster, shows a remarkable similarity, and the 

 column of atoms proves that this granite cannot consist of quartz, 

 tersilicated feldspar, and common mica. 



The soda-granites of Newry agree with the soda-granites of 

 Leinster in the reduced per-centage of silica, in the increase of iron, 

 lime, and magnesia, and in the preponderance of soda over potash. 



I hope, on a future occasion, to be in a condition to complete this 

 account of the Newry granites. 



February 15, 1856. 



Annual General MeetiJig. 

 [For Reports and Address see the beginning of this volume.] 



February 20, 1856. 

 W. Howland Roberts, M.D., was elected a Fellow. 

 The following Ck)mmunications were read : — 



