GEOLOGY OF THE MERRIMACK DISTRICT. 471 



around them, the noise of the rushing and tumbhng of the waters equals 

 some of our fierce mountain streams. South of the Ashuelot river, on 

 the road that runs west from Ashuelot village, the porphyritic gneiss ex- 

 tends to the edge of Hinsdale. South-west of Ashuelot village there is 

 an outcrop, near the house of C. Wise, and this is near its southern limit. 

 The rock in this area, as well as that in Marlow, is nearly everywhere 

 stained with iron. Near the central part of Fitzwilliam there is a limited 

 area of porphyritic gneiss. At Dr. S. Cummings's, we find a characteris- 

 tic variety. West, near the railroad, and just north of the granite quar- 

 ries, there are several outcrops, and the one north of the Richmond road 

 and east of the railroad is quite extensive. Some boulders on the road 

 from the station to the village enclose rounded masses of the dark gneiss 

 that is quarried on the Richmond road and below the station. There 

 may also be an outcrop on the east side of South pond. From the 

 State Line station on the Cheshire railroad, going north, we have White 

 Mountain gneiss, dipping north-westerly ; this is followed by a fine- 

 grained gneiss, and this in turn by a band of well-marked porphyritic 

 gneisses which extend to Sip Pond hotel, while northward are granitic 

 gneisses of the White Mountain series. 



In Jaffrey, south-west of Gilmore pond, near A. Emery's, there is a 

 small area of prophyritic gneiss. In Dublin, south of Monadnock pond, 

 there is an isolated hill near W. Phillips's, where the crystals of feldspar 

 are much smaller than those found elsewhere in the porphyritic gneisses ; 

 here they are not much more than a quarter of an inch in thickness, and 

 three quarters of an inch in length. The same rock outcrops near P. 

 Morse's, and it is associated with a pyritiferous schist, but interstratified 

 with it there is a dark, fine-grained gneiss. The dip of the porphyritic 

 rock is N. 8° W. 35°, and the pyritiferous schist is unconformable with it. 

 The rock in the south-east part of the town has many of the lithological 

 characteristics of the porphyritic gneiss, though the large crystals of feld- 

 spar are wanting, and it resembles the gneiss of Bradford. In the north- 

 east part of Dublin, and extending into Harrisville, the gneiss is porphy- 

 ritic. At J, Gilchrist's are many ledges, and there are outcrops along 

 the branch of Contoocook river to the outlet of North pond. Its western 

 boundary extends from near the forks of the road above school-house 

 No. 9, a little west of north, to D. French's, south of Long pond ; thence 



