230 Proceedings of the Royal Irish Academy. 



[Plates m.-v. are from photogi'aplis taken with the microscope 

 "by Mr. T. Crook, a.e.c.sc.i.] 



Plate III. 



Fig. 1. — Section of granite containing patches of biotite, horn- 

 blende, and epidote, derived from the materials of the schistose series. 

 South of Ardlougher, near Clooney (p. 211). x ]0, 



Fig. 2. — Section of composite rock (quartz-diorite), produced at 

 junction of granite and epidiorite. North-east slope of Derkbeg Hill 

 (p. 218). X 10. The hornblende has revived and recrystaUized under 

 the influence of the intruding granite magma. 



Plate IY. 



Fig. 1. — Section of composite rock, with brown biotite ("Lepty- 

 nolite"), produced at junction of granite and mica-schist. Small 

 quarry on road from Clooney to Maas (p. 209). x 10. 



Fig. 2. — Section of composite gneiss, inclining towards granite, 

 with delicate streaks of biotite, epidote, sphene, and some hornblende. 

 Quarry in Loughnambraddan, above Finntown (p. 223). x 10. 



Plate V. 



Fig. 1 . — Section of pure euritic aplite, with ovoid forms of consti- 

 tuents. Quarry in Loughnambraddan, above Finntown (p. 222). x 10. 



Fig. 2. — Section of schistose diorite (epidiorite), into which the 

 aplite intrudes in the quarry in Loughnambraddan, above Finntown, 

 producing a variety of composite gneisses, one of which is illustrated 

 on PI. IV., fig. 2 (p. 222). x 10. 



