520 



OGILVIE 





^=^ 





Mi 

 Pe 



:a Scfi 



St 



e 



gmat it 





£•.".;£ 





G 



™anit e 







i-xiljriljjL 





D 



Horr 



labas 

 blende 



e 

 Schist 



Fig. i. 



Geological map of Cabbage 



Island, Maine. 



Grabau's collection, and especial 

 thanks are due to him for this 

 material. 



The chemical analyses were 

 done by M. W. Adams, to whom 

 the writer is greatly indebted. 

 The methods followed were those 

 recommended by Washington in 

 his book The Chemical Analysis 

 of Rocks. The most important 

 oxides were determined in each 

 case, including both oxides of 

 iron, titanium and phosphorus. 

 The Lawrence Smith method was 

 used for the alkalies; the colo- 

 rimetric method for titanium, and 

 ammonia for the precipitation 

 of alumina, manganese being 

 neglected. The bluish-green cake 

 after the first fusion indicated 

 that manganese was present in 

 nearly every case. In the one 

 rock (a diabase) in which it ap- 

 peared to be greatest in amount, 

 it was determined on a separate 

 portion and found to be 0.35%. 

 The aim of the analyst was to 

 produce analyses that should be 

 "superior" in the sense of being 

 accurate, but which should be 

 inclusive of the rarer oxides only 

 in so far as the interest and im- 

 portance of the region seemed 

 to warrant. 



There is no recent literature 

 dealing with the area here de- 

 scribed. Diabase dikes from the 

 eastern part of the Boothbay 



