574 STRATIGRAPHICAL GEOLOGY. 



are as fully ferruginous as those in New Ipswich and Sharon, but have 

 not been separated from the others upon the map. Between the ferrugi- 

 nous portions of the Rockingham and Merrimack groups it is still more 

 difficult to draw a satisfactory line of distinction. 



The following notes may express the nature of the rocks across the 

 patch of ferruginous Montalban in New Ipswich. At the south edge of 

 Greenville are gneisses of an older period, dipping 25° W. At the cross- 

 ing of the Souhegan, by a factory, ferruginous schists hold granite beds, 

 dipping 40° N. 80° W. Taking the road to Factory village, coarse, dark 

 mica schists appear. At M. Farrar's, on the north road to New Ipswich, 

 are Montalban schists, dipping 28° N. 50° W. Half a mile south of the 

 hay-scales a mica schist with granite veins dips 35° W. The same rocks 

 occur farther south, at G. Willard's, with the same position. Taking 

 first a line to the south-west corner of the town, we find ferruginous 

 schists at the chair-shop pond. East of the summit of the mountain is a 

 dip of N. 25° E.; and a crumpled gneiss on the ridge, perhaps dipping 

 west, as a similar rock certainly does in the south-west corner of the 

 town, S. 40° W. irregularly. Returning to New Ipswich village we find 

 mica schist with granitic beds, both somewhat ferruginous. It is thick- 

 bedded, dipping 20° N. 85° W. in the outskirts of the village. By S. C. 

 Wheeler's there is a ferruginous schist, dipping 20° E. This is some- 

 what local, though it may agree with the rock having the same dip on 

 the ridge near J. Nutting's to the south, just mentioned, and to the dip 

 of N. 85° E., at the south end of Kidder mountain, to the north. At W. 

 Shattuck's it is the same. On reaching the ridge of Barrett mountain 

 the dip changes to 40° W. This is continuous for over a mile. Near 

 G. Stratton's, half a mile before reaching the west town line, the dip 

 has changed to 15° E. It is higher in the east part of Rindge, and soon 

 makes an anticlinal axis. It will be interesting to compare this section 

 delineated in Fig. 94 with that about five miles to the north, in Fig. 91. 

 On the line of Sharon, ferruginous rocks dip 80° N. 60° W. Similar 

 rocks occupy the whole of Sharon. It is conceived that Kidder, Temple, 

 Pack Monadnock, Pinnacle, and Lyndeborough mountains may be dis- 

 tinct from this group, and they will be spoken of as Rockingham schists. 

 I judge the ferruginous type of rock extends west of this into Greenfield. 



The next ferruginous group of this age is that of Dcering, occupying 



