GEOLOGY OF THE MERRIMACK DISTRICT. 5OI 



wall of rock thirty or forty feet in height, and pot-holes in the ledges 

 where the water has poured over. The strata are nearly vertical, and 

 there are granitic veins. South of the village is the granite quarry, and 

 on account of the arrangement of the mica the rock appears to be bedded. 

 It has two micas and two kinds of feldspar, — one beautifully striated. 

 South, along the railroad, there are many outcrops of micaceous gneiss ; 

 the strata are nearly vertical, with nearly everywhere an easterly dip ; 

 while along the road south of the old church the dip is westerly, thus giv- 

 ing a synclinal structure to the Montalban rocks. Here, as elsewhere, 

 these rocks frequently contain coarse granite in veins. They are quite 

 numerous on the hills east of Marlborough station. On the west of these 

 rocks we have a gneiss in the edge of Swanzey that resembles more the 

 Bethlehem than common gneiss, while on the east, in Marlborough and 

 in the edge of Dublin, we have siliceous pyritiferous schists. 



Rocks of the Montalban series are the prevailing, if not the only, rocks 

 of Troy, and many of them cannot be distinguished from those found on 

 the summit of Mt. Washington. We have east of the village a granitic 

 gneiss of this series that is quarried. The strata are generally nearly 

 vertical, but the prevailing dip is easterly. The most important thing in 

 connection with the rocks of Troy is that the Monadnock range meets 

 Montalban rocks at such an angle as to show their unconformability. 

 The western boundary of the Montalban rocks of Troy and southward 

 follows very near the line of Troy and Swanzey, and from near the north- 

 east corner of Richmond it extends in a curved line nearly to the village 

 of Richmond ; thence it extends a little south of west, and strikes the 

 town line perhaps a mile south of Peaked mountain. 



In Winchester there is a small area of these rocks in the south-east 

 corner of the town, and they may extend in a narrow band as far north 

 as the west side of Stony mountain. 



In Richmond all the rocks south-east of the line we have mentioned 

 belong to the Montalban series, with the exception, possibly, of the band 

 of rocks that embraces the soapstone. The strata generally are nearly 

 vertical, and have both easterly and westerly dips, while the strike is 

 frequently north and south. In some places the strata are twisted and 

 contorted, and so ferruginous as to disguise the real character of the rock. 

 South-east of school-house No. 14 is a band of soapstone, included, in part. 



