514 Pirsson and Washington — Geology of New Hampshire. 



Massachusetts, which has been described by one of us.* In 

 this rocks of very similar chemical and mineralogicai composi- 

 tions occur. These include numerous types, of varying modes 

 and textures, belonging to subrangs which are found at the 

 Belknap Mountains, namely: liparose (granite, aplite, paisan- 

 ite, keratophyre), lassenose (rhyolite), pulaskose (pulaskite, 

 solvsbergite), and camptonose (diabase), with essexose (essexite) 

 closely like the phyro-camptonose of Belknap. These rocks of 

 Essex County are, it is true, associated with miaskose (foyaite 

 and tinguaite) and with umptekose (solvsbergite,) but this 

 heightens rather than detracts from the analogy, as miaskose 

 and umptekose (neph elite-syenite), are found at Red Hill, 

 across Lake Winnepesaukee from the Belknap Mountains. 

 This last igneous mass will shortly be described by us, so that 

 further consideration of this correlation may be deferred. 



Still nearer to the Belknap Mountains are the rocks of 

 Ascutney Mountain, which have beeu studied by Daly,f whose 

 descriptions and analyses make clear the very close similarity 

 between the two areas. The resemblance between the two is 

 shown even in such details as the poikilitic development of the 

 alferric minerals of some of the Ascutney gabbros and diorites, 

 in this resembling the hornblendes of the gilfordal camptonose. 

 Analogies may also be noted with the rocks of the Monteregian 

 Hills, in the Province of Quebec, which have been described 

 by Canadian petrographers.if The rocks of these last, however, 

 are generally distinctly lower in silica and are more sodic, norm- 

 ative or modal nephelite being quite common. 



It would seem that all of these occurrences, with perhaps 

 others in Maine, New Hampshire, Yermont, and Massachusetts, 

 belong to one petrographic province, or comagmatic region 

 as it may be better termed, which may be called the Novang- 

 lian, from the many localities in New England. This is not 

 the place for a discussion of this region, especially as our 

 knowledge of some of the districts is as yet incomplete, but 

 some of the chemical features may be briefly pointed out. 

 These are the rarity of the dofemanes and perfemanes, the 

 prevalence of quardofelic, perfelic, and lendofelic orders, of 

 peralkalic and domalkalic rangs (alkalicalcic rangs occurring 

 to some extent among the salfemanes), and of sodipotassic and 

 dosodie subrangs. As features of minor importance may be 

 mentioned the generally small amount of MgO, even in the 

 salfemanes, the comparatively high FeOand Ti0 2 (the amount 

 of the latter being often very great in the salfemanes), and the 

 almost complete absence of BaO. 



New Haven, Conn., and Locust, N. J., June, 1906. 



* Washington, Jour. GeoL, vi, 787, 1898; vii, 53, 105, 284, 463, 1899. 

 fR. A. Daly, Bull. U. S. GeoL Surv., No. 209, 1903. 

 \J. A. Dresser, Am. G-eol., xxviii, 203, 1901; F. D. Adams, Jour. Geol., 

 xi, 239, 1903; J. A. Dresser, this Journal, xvii, 347, 1904. 



