Vi TABLE OF CONTENTS. 



LABRADOR. 



Packard's observations in 1865 ; he recognizes there, on very inadequate evidence, 

 the Laurentian and Huroniau, 381 ; labradorite rocks seen, apparently eruptive, 

 but called by him Norian, 381 ; HiXD refers the rocks of Labrador to the Lau- 

 rentian on lithological grounds, 381 ; Wilkins holds the same views, calling a 

 dike Norian, 382. 



MAINE. 



Geological Survey under C. H. Hitchcock developed nothing of value in regard to 

 the Azoic rocks, 3S2 ; Hunt infers that the mica schists and gneisses of Maine 

 are of Montalban age, and that the rocks near Portland are Huronian, and older 

 than the gneisses, 382 ; C. H. Hitchcock holds exactly the opposite view, 

 382. No evidence whatever in regard to the age of the crystalline rocks in Maine 

 other than lithological, 383. 



NEW HAMPSHIRE. 



Hunt, in 1847-48, in 1863, and again in 18.67, refers the rocks of the White Moun- 

 tains to the Devonian, 384 ; Lesley does the same, and claims for the range a 

 synclinal structure, 384 ; his probable error, 384 ; Hunt, in 1878, says that 

 Logan considered the '\\^nte • Mountains as Devonian, omitting to state the fact 

 that he himself had repeatedly published the same opinion, 384 ; Hunt, in 1870, 

 called the White Mountains Terranovan, which he considered as being in part of 

 Potsdam age, 384. C. H. Hitchcock's first scheme of the rocks of New Hamp- 

 shire, in the Report of 1869, in which most of them are refeiTcd to the Quebec 

 group, 385 ; another arrangement, in the Second Report, for 1870, 385, 386 ; in 

 the Third Report, 1870, the White Mountains are called Eozoic, which " satis- 

 factory reference " is said to " clear up the obscurities of New Hampshire 

 geology," 386 ; further changes, in Report for 1871, and introduction of the 

 Norian, "the prevalent opinion in regard to the age of the New England meta- 

 morphic rocks must be changed to couform to the discovery of labradorite in our 

 State," 387 ; Hawes, however, regards the labradorite rock as eruptive, 387 ; 

 Hunt, in 1873, accepts the Norian ; but, in 1878, says that it is found to be of 

 eruptive origin, 388 ; C. H. Hitchcock, in 1872, endeavors to prove that the 

 Norian rocks are of sedimentaiy origin, 388 ; further remarks to the same effect 

 by C. H. Hitchcock, in various papers published in 1871-72, 389 ; also, in 

 Final Report, Vol. XL, in which we are told that " the facts as interpreted [in 

 reference to the Norian or Labrador system] are of great consequence, since they 

 fix the geological horizon of the whole Atlantic system," 389, 390 ; later on in 

 the same volume, all that had been said of the Labrador system taken back, 

 the rocks recognized as being eruptive, and the exposures on Mt. Washington 

 formerly considered as stratified now called "injected dykes," 390. C\ H. 

 Hitchcock, in the Report for 1872, assigns the Quebec group to the Huronian, 

 the Concord granite said to be sedimentary, 391 ; the same author presents, 

 in the Report for 1872, a classification of the rocks of New Hampshire (see 

 Table), 391, 392; "granite flowed over the country like water," 392 ; "ten 

 distinct periods traced on the scarred sides of the White Mountains," 392 ; 



