100 



GEEEN MOUNTAINS IN MASSACHUSETTS. 



Just north of the Massachusetts state line, in Vermont, about 2 £ miles 

 northeast of the last contact, we find again the contact of the granitoid gneiss 

 with quartzite; this is in Stamford, in the hills west of the village. 1 



The granitoid gneiss has the same general characters that it has further 

 south. The contact is found near an old schoolhouse along the roadside. 

 The quartzite is micaceous and strikes north 30° to 55° east, being curved 

 a little in the outcrop and dipping 42° east; the contact is seen here within 



Fig. 28 — Contact of granitoid gneiss (Stamford gneiss) ami quartzite (Vermont formation), Stamford, Vt. Looking 

 north. 



The gneiss fills the left half of the figure. It is here very coarse, with structure feehly indicated. The hollow in 

 its center (through which the read goes) is caused by the erosion of a vertical dike of amphibolite ahout 11 feet wide, 

 which does not penetrate the quartzite. The quartzite is seen on the right, dipping southeast. 



1 foot of strata, and by digging the actual contact was found. The lamina- 

 tion of the granitoid gneiss strikes north 55° cast, dips about 40° easterly; 

 that is, in a general way conformable to the bedding of the quartzite. At 

 this place a vertical band of rock 14 feet wide strikes north 60° west, or 

 across the strike of both rocks: it has the character of the altered rocks 

 described on pages 65 to 69 and is undoubtedly a dike; this runs in a 

 straight line through the granitoid gneiss, but abuts against the quartzite 



1 C. H. Hitchcock briefly describes this locality in Geology of Vermont, p. 601. 



