Lower Palwozoic Each of the South-East of Ireland. 



591 



Table I. 

 Analyses of Orthoclase Felspar. 



All these felspars are monoclinic, and. occur in large crystals, with their 

 cleavage planes well developed ; the other faces are comparatively rare. 

 Taking the average per-centage, we find the following Table: — 



Table II. 



Atomic and Oxygen Ratios of the Orthoclase of Leinster. 



4h 2 



