GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 425 



it embraces a section of country several miles in width west of the gneiss. 

 It is developed in its characteristic form in Acworth, and there is a small 

 but important area north and east of Sam's hill in Charlestown. Just 

 north of the Langdon road, at the height of land north of Sam's hill, we 

 see plainly the super-position of the mica schist. In Fig. 64 the relation 

 of the rocks in Charlestown is shown. One thing to be noticed is that 

 the argillaceous schist, where it comes in contact with quartzite, is at 

 right angles to it, and, on account of the argillaceous schist, the quartz 

 conglomerate, and the mica schist dipping in different directions, it does 

 not show the exact relations of these rocks. The strata of argillaceous 

 schist are very much contorted, but the unconformability with the quartz 

 conglomerate is apparent, while the latter runs under the mica schist. 

 The western band of quartzite shown on this section is farther north 

 on Oak hill, vertical, so that probably its normal position, in relation to 

 argillaceous schist and the Calciferous mica schist, is an anticlinal. The 

 common gneiss is on the eastern border of the mica schist, both in 

 Unity and Acworth. In the south-east part of Langdon, and also in 

 the adjoining town of Alstead, there is a mica schist that may be a 

 continuation of that in Charlestown and Acworth. In Langdon it out- 

 crops at the forks of the road, near G. Kingsbury's on Walker's hill, and 

 many other places. At the first locality mentioned it contains andalusite. 

 In Alstead, it is found on the south-west side of Cobb's hill, where it 

 contains cyanite, which, near the surface, has undergone decomposition, 

 so that it has the appearance of mica. 



Going towards the south-east, this mica schist appears in Walpole ; 

 there are extensive outcrops on the Walpole and Surry road, especially 

 near the height of land, and it is like that of Unity and Acworth, and 

 very frequently it contains staurolite. South-east, in Surry, the strata 

 are nearly horizontal, and, as in the vicinity of school-house No. 4, they 

 rest on the protogene gneiss. The schist in the north-west part of Surry 

 and in the south-east corner of Alstead seems to be rather the argilla- 

 ceous mica schist than the common mica schist. 



In Westmoreland the principal area, and this limited, is found in the 



south-east part of the town. Here the strata are nearly horizontal ; and 



the rock occupies the top of the hill above L. Hyland's. In a following 



chapter on the gneissic area of this town, there is a section showing the 



VOL. II. 54 



