558 STRATIGRAPHICAL GEOLOGY. 



dark micaceous gneiss are interstratified here with the common variety. 

 The next ledge seen is at Reed's ferry, in Merrimack ; then at the cross- 

 ing of McOuade's brook, near its mouth, with south-east dip. At the 

 crossing of the Souhegan river, in the village, the coarse mica schists dip 

 70° S. 40° E. No related rocks appear farther south. It would appear 

 from this line of outcrops that the twisted gneisses possess an anticlinal 

 structure, and are flanked on both sides by a coarsely crystalline mica 

 schist, evidently belonging to the same general series, and not to be con- 

 founded with the Rockingham group. It is the same with that at Amos- 

 keag falls. 



The next route traversed was from Thornton's ferry, across Merrimack 

 and the south part of Amherst, to Milford. Perhaps a mile and a half 

 back from the ferry is a small ledge of the coarse mica schist with granite, 

 beyond R. H. Pratt & Co.'s, dipping 80° S. 25° E. A coarse granite 

 occurs next, west of the school-house, midway across the township. Just 

 in the edge of Amherst is a coarse granitic gneiss, dipping 50° S. 55° E. 

 This region is covered by wide-spead alluvial deposits, which greatly 

 obscure the ledges. At Danforth's Corner, or South Amherst station, 

 the very twisted gneisses appear in their characteristic development. At 

 the west town line a fine-grained granite, like the Concord, succeeds. 

 It may be seen from the road, also, about a mile and a half south of Mil- 

 ford, by means of the openings that have been made for quarrying. 

 There may be an anticlinal on this route. 



South-west from Milford there may be a similar granite as far as 

 Osgood's pond. The gneiss dips north-west by E. B. Tuck's and A. 

 Gutterson's. Taking the south row of towns next, we find the eastern 

 border of the gneiss near the town lines of Brookline and Hollis, 

 a mile north of Massachusetts, and part of this route agrees with that of 

 a section from Temple to Brookline, Fig. 91. West of F. Smith's the 

 gneiss dips south-east. By L. Sawtell's there is a coarse indigenous 

 granite, with the same position. Several varieties of gneissic rocks are 

 found near N. Farrar's, a mile west of the town line, dipping 60° S. E. 

 Next, there is a plain for a mile and a half to Brookline village, where 

 the gneiss contains distinct crystals of feldspar approaching the por- 

 phyritic variety, with the same dip as before ; here it is 65° S. 70° 

 E. A little west of the village is some mica schist and granite, dip- 



