(BB) Boulder Batholith Suite -- Montana


(BB) Boulder Batholith Suite -- Montana

Collection Items

porphyritic, light gray, fine grained

fine grained, dark gray, porphyritic


coarse grained, light gray, biotite-hornblende

ignimbrite layer in a welded tuff

flinty, columnar jointing, post-batholith volcanic

from large sill

fine grained with pinkish tint

from nearly vertical dike cutting quartz monzonite

pre-batholith volcanic

intrusive plug of quartz monzonite
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