COMPOSITION OP THE SYENITE. 251 



Hampshire rock contains original socialite, while this mineral in the 

 Maine rock is principally secondary. The former therefore is more 

 nearly a normal eleolite-syenite than is the latter, although it possesses 

 an abnormally high percentage of albite, as indicated by the high per- 

 centage of silica and the low percentage of alumina, together with an 

 excess of soda over potash. 



