Geology of New Sampshire, U.S. 127 



of the printed statements. Without giving the reasons for new- 

 views, the following may be presented as the probable ages and 

 arrangements of these metamorphic groups. 



First, of Laurentian age, is a central and interrupted area of Por- 

 phyritic gneiss and granite. This is flanked in the more southern 

 counties by wide bands of gneiss, having similar mineralogical 

 characters upon both sides, each capable of satisfactory subdivision. 

 Nest come several isolated patches of the Labradorian group of the 

 Canada Survey, or the Norian ^ of Hunt, characterized chiefly by the 

 presence of the mineral labradorite, now for the first time discovered 

 in situ in New England. An extensive compound of labradorite and 

 chrysolite has received the name of Ossipyte.^ An extensive series of 

 felsites, granites and jaspers seem to belong nearly to this period. 

 Next is a large amount of Anclaliisite gneiss, found both among the 

 White Mountains and in the southern districts. This has been re- 

 ferred to the " White Mountain Series," or the Lower Cambrian, by 

 Dr. Sterry Hunt, in his Address before the American Association for 

 the Advancement of Science, 1871. It seems to be stratigraphically 

 distinct from the Norian rocks, though not so easily separated from 

 the supposed Laurentian gneisses. All the rocks thus far mentioned 

 are clearly Eozoic, and unconformably underlie all the others. 

 Apparently the lowest of the Paleeozoic division is the series of slates 

 and schists, to which the name of Coos group has been given in the 

 second report. This is synonymous with Hunt's Terranovan series 

 in part, by him referred to the base of the Silurian. In New Hamp- 

 shire this group contains the minerals andalusite, staurolite, and syenite 

 in great abundance ; or silicates of alumina without alkalies. A 

 great band of it lies along Connecticut river for over a hundred 

 miles, invariably resting upon the edges of the Eozoic gneisses. Its 

 stratigraphical relations were determined before the suggestion of the 

 term Terranovan. A band of mica-schist and quartzites along the 

 Merrimack river must be of nearly the same age. This " Merrimack 

 group" occasionally carries andalusite schists, and crops out upon 

 Mounts Pequawket and Washington. Next come the green schists 

 usually called talcose, and the equivalent of the metamorphic portion 

 of the " Quebec Group " of Sir W. E. Logan. This is found along 

 Connecticut river, widening in the extreme northern part of the State. 

 Eecently Credner, Macfarlane, and Hunt have referred this talcose 

 band to the Huronian of Logan, which is probably Eozoic. Scattered 

 over this Quebec area are several patches of clay-slates ; two of the 

 "Calciferous Mica Schist" of the Vermont Eeports, and one of Helder- 

 berg limestone (Devonian), with fossils. The slates are allied to the 

 " Gaspe slates " of Canada, which are thought to be Upper Silurian. 

 Logan refers the mica- schists to the same age. 



New Hampshire furnishes a fine field for the study of the mark- 

 ings left during the Glacial period. Transported boulders have been 

 discovered 5,800 feet above the sea-level upon Mount Washington. 

 The striae at 5,200 feet course south-easterly, and indicate that the ice 

 moved up and over the peaks. In other parts of the State the strise 



^ Amer. Joum. Sci., 11., vol. xllx,, p. 180. ^ Ibid,, HI., vol. ill., p. 49. 



