GREEN MOUNTAIN GNEISS. 463 



Massachusetts stratum of mica schist becomes gneiss extremely near the State line, by 

 the addition of a little feldspar. It is a case of the metrmorphism of one rock into an- 

 other. 2. The examination of the rocks of the two States has brought to light what would 

 never have been discovered in either State by itself, viz : that there is a narrowing of the 

 formations very near the State line. Both the gneiss formation and the talcose schist 

 curve to the westward ; so that in Massachusetts the mica schist and gneiss are narrower 

 than in Vermont. The beginning of this bend in the strata may be seen upon our geolog- 

 ical map, but it cannot be appreciated except upon a map of the two States conjoined, or 

 upon a geological map of New England. 



The eastern part of this range as it first appears in Vermont, is very distinct gneiss, 

 and was mentioned as such in the Geological Reports of Massachusetts. It lies much to 

 the east of the Green Mountains, in the towns of Wilmington, Readsboro, and Whiting- 

 ham. That which forms the axis of the Green Mountains, in the southeast part of 

 Stamford, is scarcely distinguishable from mica schist. The eastern limit of the gneiss 

 in the first tier of towns is at Jacksonville, the western is half a mile west of the village 

 of Stamford, where it loses itself in granite. In the village of Stamford, and at Hartwell- 

 ville, the gneiss almost passes into quartz rock, and the same belt of rock continues to the 

 north part of Searsburgh. In Whitingham and Readsboro there is a large amount of 

 dolomite and saccharoid limestone present in the gneiss in the form of beds. The gneiss 

 west of Deerfield River in Readsboro is rather peculiar. It is a very coarse, greenish, 

 massive rock, sometimes containing multitudes of garnets, and blotches of what re- 

 sembles clay slate. A belt of it has been traced more than a mile in width, from 

 Readsboro to West Wardsboro. Most of the course of Deerfield River in Vermont lies 

 in the trough of a synclinal. Hence the strata of gneiss in a part of their course, as in 

 Wilmington, are nearly horizontal. 



The gneiss upon Section II, in the second tier of towns north of the State line, is better 

 characterized than upon Section I. The west part of the gneiss, in Woodford, Glasten- 

 bury, Somerset, Stratton, Sunderland, Winhall, etc., is mostly covered by drift, so that 

 its characters are but imperfectly known, and its position is uncertain. In the north 

 part of Readsboro the feldspar is abundant, and the strata run nearly east and west, and 

 stand upon their edges. The structure of the gneiss in Woodford may be surmised by 

 examining the rocks upon Deerfield River, in Searsburgh and Somerset. Some of it is 

 deficient in mica, but feldspar is everywhere abundant, and there are two or three axes, 

 which probably continue into Woodford. Besides the drift, a more serious obstacle to 

 the acquisition of knowledge of the character and position of the gneiss in the towns 

 specified above, exists in the absence of roads, and the scarcity of inhabitants. We have 

 not had, during our explorations, any facilities for the examination of a wilderness. 



In the west part of Wardsboro the gneiss is rather obscure, but in a large number of 

 towns to the north, in fact everywhere south of Mount Holly, the gneiss is well 

 characterized. In Jamaica it superabounds in feldspar, and near the village becomes 

 granitic. Along the route of Section V. in Mount Holly and Wallingford, the range is 

 a little more than half its width at the State line. Upon the east part of this section the 

 gneiss is unusually obscure, and has been mistaken by some for talcoid rocks. The west 

 side of the anticlinal displays its gncissoid character more perfectly, as well as the 



