CONTACT AROUND BELCHERTOWN TONALITE. 245 



greeu pyroxene grains, with here and there a great black hornbh-nde crystal 

 appearing jjorphyritically in the mass, its shining surfaces luster-mottled 

 by many grains of the ])ale-green pyroxene, which are here better crystal- 

 lized and smaller than in the main mass. The pyroxene is colorless, witliout 

 pinacoidal cleavage or inclusions of any kind. 



This is the rock that was called augitic syenite by President Hitch- 

 cock, and slides were cut from the specimen in the survey collection (XVIII, 

 92). The rock contains large leek-green crystals of pyroxene, large black 

 hornblendes, and a scanty granular groundmass of plagioclase. 



Iji slides the dark-green hornblende, which is at times brown centrally, 

 is luster-mottled on its broad cleavage surfaces with pyroxene, which is 

 faintly reddish, of high refraction and coarse cleavage. The large pyrox- 

 enes are intergrown with iiregular portions of hornblende with the axes a 

 and h of the two minerals parallel. In sections normal to h the cleavage 

 lines coincide and a revolution of 17° to 19° brings the hornblende to 

 extinction, and of 43° in the same direction, the pyroxene. The two min- 

 erals are so interwoven that they give almost an aggregate polarization. 

 Small, brown octahedra appear in the hornblende. In general the amphil)- 

 olite is not made pyroxenic, but is only crushed and tilled with quartz veins. 

 It is the usual flat-fissile, dark, fine-fibrous rock. 



Samples from an artesian well, bored on the grounds of Mr. Myron P. 

 Walker, in the center of Belchertown, taken at the depths indicated, g^iA-e 

 the following results: 



Record of an artesian-tcell boring in Belchertown. 



80 to 100 feet, pegmatite. 



115 feet, grauite, with little ampliibolite. 



130 feet, granite, with little amphibolite. 



145 feet, grauite. 



160 feet, granite. 



175 feet, yellow granite, with much muscovite. 



190 feet, gray granite, with amphibolite. 



205 feet, gray granite, muscovite, and amphibolite. 



220 feet, gray grauite, muscovite, and amphibolite. 



249 feet, much coarse biotite. 



Still farther south, on the west slope of Baggs Hill, in Granby, appear 

 dark greenish-gray, membranous, feldspathic mica-schists, associated with a 

 quartzite which is at times blackish, at times greenish, and abounds in (piartz 

 crystals and pvrite. 



