SOME EXAMPLES OF ROCK VARIA TION 



387 



Chemical relations of tlie series.- — In the preceding pages the 

 mineralogical evidence has been given of the variations under 

 discussion. In the following tables there are reproduced the 

 analyses which have been given of the typical members of the 

 different classes. They are arranged in order of diminishing 

 acidity. In Table I the complete analyses are given. 



99.46 



100.63 



100.17 



99.17 



II. 



PERCENTAGES OF CHIEF OXIDES REDUCED TO IOO. 



