666 STRATIGRAPHICAL GEOLOGY, 



areas are intimately connected with the eastern band. These two groups, 

 then, are older than the greenstones. In Hanover the apparent ascending 

 order is this: first and lowest, Bethlehem gneiss with the Coos schist on 

 its flank; next, hornblende schists; then the greenstones, followed in 

 Norwich by the clay slates and calcareous rocks. This is apparently 

 the natural order of age, the arrangement of the last three members 

 having been already decided upon, and it shows the hornblende rocks 

 and greenstones to overlie the Bethlehem group. It is more difficult 

 to define between the Montalban and greenstones. A section from 

 Success across to Dummer shows the greenstones bordered on both 

 sides by Montalban, dipping south-easterly. In case the eastern area 

 is anticlinal, as seems probable from the few facts at command, we 

 have a clear case of a Montalban basin supporting greenstones, making 

 the latter the newer rock. Our section in Fig. 5, p. 54, shows a Montal- 

 ban anticlinal flanked by greenstones upon both sides. In Concord and 

 Granby, Vt., is an anticlinal mass of Montalban rocks crossing Sections 

 X and XI, having the anticlinal structure. Upon the east side are green- 

 stones, and on passing to the next group east we find the Lake gneiss. 

 This section from Concord or Granby to Lancaster would afford another 

 synclinal basin of gneiss supporting the greenstones, but only one of 

 them is Montalban. Essex county, Vt., shows a large amount of ancient 

 rocks, evidently older than the formations of the Connecticut, Passump- 

 sic and Clyde river valleys. Looking to the south-west we find, half way 

 through Vermont, the gneiss range of Hartland and Athens. It seems 

 natural to believe there may be some connection between these gneisses 

 of Essex and Windham counties. This is important only as it carries 

 out the general correspondences of age in different parts of the Connecti- 

 cut valley. Between the Windham and Cheshire county gneisses is a 

 narrow strip of greenstones, seemingly in a basin. The eastern range is 

 continuous to the more northern section across Lancaster to Granby, 

 where one sees gneisses as before in Windham county, and would natu- 

 rally consider its relations of comparative antiquity to the greenstones 

 the same. Though the gneissic ridge is not continuous between Essex 

 and Windham, the greenstones may take its place in the gap, certainly 

 so far as it is related to the superior slates and limestones upon both 

 sides. 



