158 Scientific Proceedings, Royal Dullin Society. 



DESCRIPTION OF PLATES. 



Plate IV. 



Polished surface of orbicular granite of Mullaghderg. The white band 

 on the slab represents one decimetre. 



A, B, fairly normal biotite-granite of the cauldron. C, D, spherulites 

 with granite cores, which have reacted on the inner surfaces of the radial 

 zone (the scale of the photograph does not allow all the details of "stoping" 

 in this zone to be seen). The form of C has influenced its neighbour D. 

 E, elongated spherulite, with a flake of biotite-schist as a nucleus, surrounded 

 by a zone of granite, outside of which the radial zone occurs. F, elongated 

 spherulite, with schistose core, into which red porphyritic felspars pass from 

 a thin surrounding zone of granite. The form has been influenced by a 

 neighbour on the right. 



Plate V. 



Polished surface of the back of the slab shown in Plate IV, the 

 interval between the two surfaces being 5 cm. The white band represents 

 one decimetre. 



G, the normal biotite-granite, with darkening by partially assimilated 

 material in streaks and patches. H, vein of later granite of aplitic type, 

 cutting the spherulite I and the main granite. I, the same spherulite as 

 that shown at D in Plate IV, with resorption and foundering on the inner 

 side of the radial zone. K, spherulite destroyed on one side by melting. 

 L, the same spherulite as F in Plate IV. 



