GEOLOGY OF THE MERRIMACK DISTRICT. 581 



Others mentioned, the dip is N. 85° E. A narrow band of rock has been 

 stated to continue southerly from this mountain to J. Nutting's, on the 

 east side of the Barrett Mountain range, a mile north of Massachusetts. 

 It may represent this formation. Barrett mountain, being more gneissic, 

 is thought to be older. Accepting the correctness of the identity of the 

 rocks of these several mountains, it would appear that the strata have 

 been pushed into an anticlinal form, while the dips are very small. This 

 range presents greater resemblances to the Monadnock rock than any of 

 the others described. 



Mt. William. In Weare, Mts. William and Wallingford are composed 

 of this mica schist, dipping 70° N. 40° W. 



T/ic Deny Range. This is the most important of all, since it stands 

 closely connected with the Merrimack group. It covers a greater area 

 on the Coast than the Merrimack district. Entering our field of descrip- 

 tion at Derry, it crosses into Nashua and Hollis, and then leaves the 

 state, being identical with the mica schist group crossing through Mas- 

 sachusetts past Lancaster, Sterling, and Worcester nearly to Connecticut. 

 The best idea of it, as it occurs in this district, may be gained from an 

 examination of a section through Derry (Fig. 100). The mica schist 

 adjoins gneiss in the south-east corner of Manchester, having a south- 

 easterly dip. Just in the edge of Londonderry is a feldspathic layer. A 

 band of white quartz, similar to others that have been prominently de- 

 scribed, crosses the section midway through the north-east corner of the 

 town, near a school-house. Other ledges of mica schist occur between 

 the school-house and the west line of Derry, dipping to the south-east. 

 Commencing with the Derry line, we find next a rock consisting of crys- 

 talline feldspar, extending, by measurement, two hundred and eighty rods 

 along the route of the section, dipping south-east. A few rods of it dip 

 north-west at the Upper Shields pond. Next follows a quartzite contain- 

 ing numerous segregated quartz bands or veins, dipping about 85° N. 

 30° W. Near W. Palmer's begins a series of regularly-bedded mica slates, 

 dipping 80° S. E. These extend as far as Beaver pond. The face of 

 the country varies according to the nature of the underlying rocks. 

 Over the feldspathic area the soil is barren ; but excellent farms cover 

 the slate area. 



There is a feldspathic rock at Derry west village, with uncertain dip. 



