282 GEOGNOSY OF THE APPALACHIANS. [XIII. 



"New Brunswick alone small areas of palaeozoic sediments which 

 are shown by their organic remains to belong to not less than 

 five periods, namely, Menevian, Lower Helderberg, Chemung, 

 Lower Carboniferous, and Carboniferous, all perfectly well dis- 

 tinguished, and each reposing directly upon the ancient crys- 

 talline rocks, we are prepared for a history not less varied and 

 complex for the rocks belonging to Eozoic time. (See the 

 author's Address before the American Institute of Mining En- 

 gineers, in their Proceedings for February, 1873.) 



Professor C. H. Hitchcock, from the results of the Geological 

 Survey of New Hampshire, now in progress, announces, in 1873 

 and 1874, a large number of divisions in the crystalline rocks 

 of this State. The Norian series there, according to him, rests 

 unconformably upon ancient gneisses, which, as he suggests, be- 

 long perhaps to the Laurentian, the appearance of which in north- 

 eastern Massachusetts I pointed out in 1870. With the Norian 

 he has however included a great series of granites and of compact 

 felsites, some of which, from specimens, appear identical with the 

 orthophyres of our eastern coasts, of Lake Superior, and Missouri. 

 These, so far as my observations go, are in no way related to the 

 Xorian, but probably belong to the Huronian series. (Ante, page 

 187.) Besides these, he recognizes the "White Mountain series 

 of gneisses and andalusite-schists (Montalban). He describes, 

 under the name of gneiss, the so-called granites of Concord 

 and Fitzwilliam, which I had already, in 1870, declared to be 

 gneisses associated with the mica-schists' of the Montalban 

 series. (Ante, page 188.) This series he supposes to be more 

 ancient than the well-characterized Huronian rocks of the State ; 

 but admits in addition a 'second and more recent series of mica- 

 schists with andalusite and staurolite, named the Cob's group. 

 Further researches in this disturbed region will be required to 

 determine whether, besides this series of andalusite and stau- 

 rolite-bearing mica-schists, which (associated with gneisses) 

 occurs in other regions, as I have in the previous pages of this 

 essay endeavored to show, above the Huronian, there is another 

 and an older series of similar rocks, or whether the two are one 

 and the same series, repeated by stratigraphical accidents.] 



