ELIZABETHTOWN AND PORT HENRY QUADRANGLES 



59 



one followed long enough after the other to have permitted the first 

 to quite thoroughly cool. The specimen came from a boulder in 

 the bed of the Branch, 2^ miles west of Elizabethtown. 



The dikes sometimes present extremely interesting exposures. 

 Figure 9 was sketched in the north fork of Walker brook in the 

 extreme southwest corner of the Elizabethtown sheet. It shows 

 some very striking little faulted blocks of a dike in anorthosite. 

 Presumably the dike was once continuous but in being broken and 

 separated into the little blocks it held its sharply angular form 

 while the anorthosite which is here much crushed and granulated, 

 molded around it. Figure 10 shows a dike in a jagged crevice. 

 Figure 7 is a map of a small dike which appears in, the bed of the 

 Branch just above the mill, about a mile or less on the stage road 

 from the Windsor hotel to the Keene valley. It can be followed 



Fig. II Network of basaltic dikes in anorthosite and crossing the bed of Slide brook 

 The dikes strike n. 45° w. 



in the bed of the cascading brook from one end to the other. 

 Figure ii illustrates an interlacing network of dikes. 



These dikes must have entered the wall rocks under very great 

 pressure, and while in a state almost as fluid as water, must have 

 penetrated every little crevice and crack open to them. They ob- 

 viously followed the chief structural lines of weakness, and prob- 



