638 STRATIGRAPHICAL GEOLOGY. 



Section II. 



The second section commences at Seabrook, at the south-east corner 

 of the state, and passes through the towns of South Hampton, Newton, 

 Kingston, Hampstead, Dcrry, Londonderry, Litchfield, Merrimack, Am- 

 herst, Milford, Wilton, Temple, Peterborough, Jaff rey, Marlborough, Swan- 

 zey, and Chesterfield, a distance of ninety miles. About five miles of 

 Vermont are appended, in the town of Brattleboro'. 



The very east end of the section consists of the northern termination 

 of the Newburyport range of sienitic rocks, overlaid by thick deposits of 

 sand and marine mud. There are exposures of a granitic rock traversed 

 by segregated veins in the marshes, which may underlie the sienite. 

 There is about a mile width of Merrimack schists to the west of the 

 crystalline masses, extending a short distance beyond Seabrook village, 

 which are much disturbed by miscellaneous trap dykes. They seem to 

 stand very nearly on edge. One of the large feldspathic masses common 

 in this group is found a short distance west of the village. From there 

 no ledges can be found for eight miles, because they are concealed by 

 the enormous development of lenticular drift hills. The rock is thought 

 to be the same with that in Seabrook. Through Newton and Plaistow 

 the dips are north-westerly, and of material suggestive of the Rocking- 

 ham group, save the first ledge in South Hampton, The dip changes so 

 as to furnish a synclinal in Hampstead, and an inverted anticlinal next 

 the ancient range of gneiss extending from Hampstead village to the 

 Nashua & Rochester Railroad in Derry. In this are some minor undu- 

 lations, but the general inclination is westerly, to underlie the broad mica 

 schist belt in Derry, Londonderry, and Litchfield. The structure of this 

 last is usually synclinal, the axial line running through the east part of 

 Londonderry. In the west part of Derry are argillaceous schists, the 

 highest part of the series possibly belonging to the Merrimack division. 

 Extensive feldspathic or granitic beds prevail in the outer parts of this 

 basin upon both sides. Litchfield shows no rocks, being covered by 

 sand. The next group is the ancient twisted gneiss of the Manchester 

 range. At Souhegan village are outcrops of a very coarse mica schist, 

 seemingly the upper layer of the formation, and repeated on the other 

 side of the fold. This last axis is a very marked one, the ridge line con- 



