1-M A. Wandke — Intrusive Rocks of 



are schistose. On Gerrish's Island the rock is fine- 

 grained, the banding characteristic of the typical gneiss 

 being absent. As narrow stringers of feldspathic mate- 

 rial penetrate the rock it loses its sedimentary habit. 

 The feldspathic stringers may increase in size until 

 they attain a width of fifteen feet. The entire occur- 

 rence is suggestive of the feldspathization described by 

 Wherry 11 in the pre- Cambrian highlands of eastern 

 Pennsylvania. On Newcastle Island the process of 

 feldspathization is well marked, and the gneisses become 

 distinctly granitized. 



A number of dikes cut the gneisses, but in not a single 

 instance in the good exposures along the coast has the 

 metamorphism so characteristic of the gneisses affected 

 a dike. Since some of these dikes are earlier than the 

 batholiths (to be described later) the period of graniti- 

 zation and feldspathization must be earlier than the 

 period of batholitic intrusion. 



Grouped with these gneisses are some rocks which sug- 

 gest altered basic volcanic flows. These have not been 

 studied in detail. 



Sedimentary Bocks Upper Carboniferous in Age. 



General Statement. — The Upper Carboniferous rocks 

 form a single group consisting of two formations. The 

 Kittery quartzite is the older of these and the Eliot 

 phyllite the younger. Boundary lines between the two 

 cannot be drawn with any great degree of accuracy, 

 and the lack of exposures and the prevalent glacial drift 

 prevent a close correlation. The two formations appear 

 to be conformable. 



Kittery Quartzite. — The typical Kittery quartzite is 

 found just north of the bridge of the York Harbor and 

 Beach Railroad that crosses Spruce Creek in the town 

 of Kittery, Maine. At this locality the formation con- 

 sists of a series of thin beds of red phyllite that alternate 

 with thicker strata of a dense fine-grained grayish green 

 or bluish quartzite. Variations from the normal are, 

 however, abundant, the differences being due in part to 

 primary causes during the time of deposition and in part 

 to secondary changes during and after the period of fold- 



11 Paper read before the Geol. Soe. of America, 1916. 



