proceedings: botanical society 199 



rocks of the Rochester. New Hampshire, basin include the Gonic for- 

 mation, in a belt 2 to 4 miles .wide running from Sanford, Maine, to 

 Barrington, New Hampshire, made up of gray wacke schists, mica schists, 

 and garnet -staurolite phyllites; the Rindgemere formation, occupying a 

 broad area in Rochester, New Hampshire, and Acton and Lebanon, 

 Maine, and lying northwest of the Gonic formation, is composed of 

 quartzite, slates, and mica schists, but predominantly of carbonaceous 

 sericite phyllites which contain chiastolite; and the Towow formation, 

 in the town of Lebanon, Maine, and surrounded by the Rindgemere 

 formation, consists of graphitic and pyritiferous quartz slates and car- 

 bonaceous sericite phyllite. 



The igneous rocks are grouped as: (1) pre-Carboniferous granites, 

 pegmatites, and diorites; (2) late Carboniferous or early post-Carbo- 

 niferous schistose granodiorites ; (3) post-Carboniferous biotite and 

 muscovite-biotite granites, pegmatites, and hornblende diorites; and (4) 

 probably Triassic trap dikes. 



The distribution of these rocks was shown on maps on which the 

 rocks of southwestern Maine and southeastern New Hampshire were 

 systematically arranged for the first time. Earlier efforts had resulted 

 only in conflicting petrographic categories without stratigraphic meaning. 

 It is now known that instead of being pre-Cambrian or early Paleozoic 

 rocks, as all had been supposed to be, more than half of the rocks, 

 areally considered, are Carboniferous (Pennsylvanian?) or younger. 

 The other rocks are in part certainly, and the remainder probably, pre- 

 Cambrian. 



Discussion: Brooks, La Forge, Paige, Loughlin, Ami, and White 

 called attention to the difficulties in establishing age relations, owing 

 especially to the lack of fossils and to the disturbed and metamorphosed 

 conditions of the rocks. The fact that a very definite trend in the struc- 

 tures had been established was emphasized as establishing relation- 

 ships with the rocks of eastern Massachusetts. 



H. E. Merwin, Secretary. 



THE BOTANICAL SOCIETY OF WASHINGTON 



The 118th regular meeting of the Society was held in the Assembly 

 Hall of the Cosmos Club, at 8 p.m., February 6, 1917; forty-four mem- 

 bers and fourteen guests present. 



Dr. B. T. Galloway, Mr. Chas. F. Deering, and Prof. W. D. 

 Crocker were elected to membership. 



The program of the evening was The relation of plant succession to 

 forestry and grazing. 



Mr. C. G. Bates stated that foresters were first to apply in a prac- 

 tical way the knowledge of plant succession, and were in a sense the 

 progenitors of this type of ecological science. The natural regenera- 

 tion of forest stands in each of the climax formations of .the Rocky 

 Mountain region was shown to involve succession, there being in nearly 

 all cases temporary control by a sub-climax following the disturb- 



