70 THE CAMBRIAN. [bull. 81. 



NEW HAMPSHIRE. 



In the final report of the geology and mineralogy of New Hampshire, 

 Dr. C. T. Jackson describes the Cambrian system as understood by him 

 at that time, and states that metamorphic Cambrian rocks occur iu 

 New Hampshire, but they contain no fossils. He also says : 



The oldest transition, or Cambrian rocks, occur in Maine and Vermont, and dip in 

 opposite directions, indicating an anticlinal axis in New Hampshire. 



On the eastern side of this axis we discover the first distinct fossils in the slate 

 strata on the Kennebec River, where the strata dip boldly to the northwestward. 



On the western side we have not yet determined the limits of the Cambrian fossils, 

 but indistinct remains of organic substances, whose nature is problematical, occur in 

 the neighborhood of Castleton, and along the western (lank of the Green Mountains. 

 They were supposed by Dr. Carr, who first noticed them, to be graptolites, which are 

 supposed to be allied to sea-pens. Graptolites are described by Murchison as belong- 

 ing to the lower part of the Silurian system. He states, however, that these pen-like 

 serrated fossils have a great vertical range in the older or protozoic rocks, being found 

 from the lower part of the Ludlow formation down to very ancient beds in the Cam- 

 brian system. 



Should these fossils prove to be graptolites, they would indicate the proximate limits 

 of the Cambrian rocks on the western side of the New Hampshire anticlinal axis, 

 where the strata dip to the southeastward. 



It will be observed that the strata become more and more recent as we proceed 

 eastward and westward from this axis, as is proved by order of superposition, litho- 

 logical characters and fossil contents of the rocks. \j 



Prof. Hitchcock says 2 that the term Cambrian is misapplied by Dr. 

 Jackson, and the ideal section showing the structural geology is incor- 

 rect in many of its details. In the final report of the second geological 

 survey of New Hampshire he describes the Rockingham mica-schist as 

 an uncouth mica-schist. The Merrimack group is a micaceous quartz- 

 ite that has not yet been fully separated from the previous group. It 

 abounds in beds of coarse, indigenous granite, which seem to have been, 

 altered in situ from the feldspathic conglomerate. Iu certain parts of 

 Strafford County the granite beds predominate, forming numerous hills, 

 while the slate occupies the valleys between. 3 Some schists with inter- 

 bedded clay slates which are referred to the Merrimack group, are sup- 

 posed to be equivalent to the Paradoxides beds of Massachusetts. 



The Connecticut Coos period can easily be divided into three parts : first, the epoch 

 of the deposition of the mountain masses of silica; second, of hornblende and mica 

 schists ; third, of limestone. 4 



In the White Mountain region there are several small areas of andalusite slate, 

 supposed to be the equivalent of the Coos group. h * * * The Coos period was 

 terminated by eruptions of syeuitic granite. * * * * The Coos quartzite now 

 constitutes a distinct range of mountains. 5 



The Mount Mote conglomerate is formed of an eruption of igneous 

 material cementing together the slaty fragments. This is included in the 



'Final report on the geology and mineralogy of tho State of New Hampshire, with contributions 

 towards the improvement of agriculture and metallurgy. Concord, 1844, p. 14. 



2 History of the Geological Surveys in New Hampshire. Geology of New Hampshire, vol. 1, 1874,p. 11. 



3 Physical history of New Hampshire. Geology of New Hampshire, Concord, 1874, vol. 1, p. 536. 



4 Op. cit,, p. 537. • Op. cit., p. 538. 



