NEW ENGLAND APPALACHIAN SYSTEMS 



173 



Two principal stages of deformation are distinguished. During the earlier 

 stage the rocks were folded, and a schistosity was developed nearly parallel to 

 bedding. Throughout the area the minor folds of this stage indicate a consistent 

 upward movement of rocks on the east with respect to those on the west. The 

 folds plunge at low to moderately steep angles, typically northward. 



Phenomena associated with the later stage of deformation decrease in 

 intensity both eastward and westward from the belt underlain by the calcareous 

 Waits River formation. At a distance from this formation, the rocks have 

 prominent slip cleavage, and the earlier schistosity is folded. The minor folds 

 plunge moderately to steeply northward on the western side of the area and 

 ^ore gendy northward on the eastern. As the Waits River formation is 

 approached, slip cleavage passes gradually into a schistosity that obliterates 

 the earlier schistosity, and the intensity of later folding increases. In both 

 the eastern and the western parts of the area the later minor folds indicate 

 "that the rocks of the Waits River formation have moved upward with respect 

 | to the formations on either side. 



1 The central part of the belt underlain by the Waits River formation is marked 

 (l by a huge arch, 10—20 miles across, whose axis is more or less parallel to the 

 1 belt and plunges gently northward. This is shown to be an arch, not in bedding, 

 )! but in the later schistosity and in the axial planes of large isoclinal folds that 

 1 were formed during the later stage of deformation. The axial planes of three 

 1 of these large isoclinal folds can be correlated across the crest of the cleavage 

 arch at Strafford Village. 



Western, Central, and Northern New Hampshire 



i Stratigraphy. A series of metasedimentary and metavolcanic rocks in 

 1 western, central, and northern New Hampshire ranges in age from Ordo- 

 vician (?) to Lower Devonian and has an aggregate thickness of 16,000 

 feet. See Fig. 11.18. Figure 11.21 is a columnar section of the Littleton- 

 ,i Moosilauke area in the White Mountains of west central New Hampshire. 

 The stratified rocks fall into six major units. The Albee, Ammonoosuc, 

 and Partridge formations are of pre-Silurian, probably Upper Ordovician 

 age, the unconformably overlying beds are the Clough conglomerate and 

 J Fitch formation of Silurian age, and the Littleton formation is of Lower 

 ; Devonian age. The Albee was originally a shale and sandstone formation, 

 land although no fossils have been found in it, it appears to be above the 

 i fossilif erous Middle Ordovician of Vermont (Billings, 1937). 



The Ammonoosuc volcanics consist principally of soda-rhyolite, soda- 

 rhyolite volcanic conglomerate, meta-andesite porphyry breccia, and slate 

 and impure quartzite. The Partridge formation is largely a black slate. In 



WHITE MOUNTAIN 

 I PLUTONIC-VOLCANIC SERIES 



aJV 



t''"j;J3 NE * HAMPSHIRE _ fiU£B££. 



\ ""t'-\ PLUTONIC SERIES /" "V VT (V- S 



);-/J PROBABLY OF NEW HAMPSHIRE 

 PLUTONIC SERIES^ 



OLIVERIAN PLUTONIC 

 SERIES FORMING CORES 

 OF D 



Fig. 11.20. Major structures of eastern Vermont and New Hampshire. After White and 

 Jahns (1950) and Billings (1956). The narrow Connecticut Valley synclinorium lies between the 

 Northey Hill and Ammonoosuc thrusts and is not labeled on the map. Osp, Standing Pond 

 volcanics; On, Northfield slate; Oo, Ottauquechee phyllite. 



