MESOZOIC--Rocks probably related to White Mountain Plutonic-Volcanic Suite of Cretaceous to Triassic age Alkali-olivine basalt and associated basaltic breccia in plug at west edge of Old Speck Mountain quadrangle Alkali gabbro and syenite at Androscoggin Lake in the Livermore Falls quadrangle DEVONIAN--Rocks principally of New Hampshire Plutonic Suite of Devonian age, but includes petrologically unrelated varieties. Age relationships not completely known, but felsic rocks typically intrude more mafic varieties Biotite-and hornblende-biotite granite and granodiorite--Predominant rock of the Hartland pluton, which grades unsystematically from dark granodiorite to lighter colored quartz monzonite and biotite granite; commonly has phenocrysts of plagioclase near border. Scarce thin dikes of pegmatite and aplite exposed near western margin. Contains accessory garnet and accessory muscovite near margins. Isotopically dated 36018 m.y. (Dallmeyer and others, 1982; Rb/Sr whole rock) Pegmatitic granite, pegmatite, and aplite--Largest body shown is subhorizontal sheet that caps Whitecap Mountain, in the Rumford quadrangle. Also forms innumerable small dikes, concordant lenses, and locally extensive subhorizontal discordant sheets that intrude two-mica and older plutonic and metamorphic rocks; rarely more than 15 m thick. Most are mineralogically simple bodies of quartz, albite, microcline, micas, scattered black tourmaline, and sparse pink garnet, but several contain beryl and a few are famous rare-mineral localities, as at Newry Mines and Black Mountain in the Rumford quadrangle (Moench and Hildreth, 1976). Most abundant in sillimanite zone. Associated with most plutons of tonalitic to granitic composition but predominantly is late differentiate of two-mica granite. Forms scarce thin dikes in Bald Mountain pluton and near western margin of Hartland pluton; not reported in Russell Mountain pluton Biotite-and hornblende-biotite quartz diorite to granodiorite and two-mica granite--Foliated rocks of unit Dqg intruded by subequal amounts of unfoliated two-mica granite of unit Dgt Two-mica granite--Predominantly pale gray, fine to medium grained, equigranular, massive or weakly foliated; locally contains two-mica granodiorite or muscovite granite, and commonly intruded by pegmatite and aplite. Variably contains accessory garnet, tourmaline, sillimanite, magnetite, zircon, and apatite. Two-mica granite of Mooselookmeguntic batholith isotopically dated 37916 m.y. (Moench and Zartman, 1976; Rb/Sr whole-rock) Biotite granite--Predominant rock of north lobe of the Lexington batholith. Light colored, coarse grained, equigranular;
