154 A. Wandke — Intrusive Rocks of 



such as those along the South side of York Harbor and 

 along the northeastern side of Brave Boat Harbor. _ The 

 Brave Boat Harbor granite is highly cataclastic. Neither 

 body presents unusual characteristics. 



Emplacement of the Intrusives. 



Elongation. — The map shows that each of the larger 

 intrusive bodies is distinctly elongated in a northeasterly 

 direction, which corresponds in a general way to the 

 dominant direction of folding for this region. In this 

 respect they conform to one of the characteristics of 

 batholiths as postulated by Daly, 15 that they should be 

 elongated in the direction of the orogenic axes. 



Method of Emplacement. — The contacts of each of the 

 large intrusive bodies have been traced as carefully as 

 the exposures would admit. The mapping has shown 

 that they are distinctly cross-cutting. Contact breccias 

 are decidedly common and within each of the intrusive 

 bodies are " islands'' of the invaded sediments whose 

 strike and dip corresponds with that of the nearby 

 country rock. These inliers are unquestionably roof 

 pendants. The map on an earlier page will better show 

 the relationships. The question of the isolation of the 

 roof pendants becomes vital in considering the emplace- 

 ment of the intrusives. Without going into the details 

 as to how this emplacement was effected, the following 

 table is offered in support of the method that seems to 

 have played an important part : 



Specific Gravities } Q 



Temp, in Centi- Solid Molten 



grade 20 1000 1100 1200 1000 1100 1200 



Sediment 2.71 2.67 2.66 2.65 i 



Gabbro 2.92 2.85 2.84 2.83 2.67 2.66 2.65 



Quartz diorite. 2.81 2.77 2.76 2.75 2.58 2.57 2.56 



Alkaline granite 2.67 2.63 2.62 2.61 i 2.38 2.37 2.36 



The tabulated specific gravities indicate that a frag- 

 ment of sedimentary rock similar to the Kittery quartz- 

 ite in composition would tend to sink in a magma having 



15 Igneous Eocks and Their Origin, 1914. 



10 Day, Sosman and Hostetter, this Journal, vol. 37, 1914. 



