(BB) Boulder Batholith Suite -- Montana


(BB) Boulder Batholith Suite -- Montana

Collection Items

intrusive plug of quartz monzonite

pre-batholith volcanic

from nearly vertical dike cutting quartz monzonite

fine grained with pinkish tint

from large sill

flinty, columnar jointing, post-batholith volcanic

ignimbrite layer in a welded tuff

coarse grained, light gray, biotite-hornblende


fine grained, dark gray, porphyritic

porphyritic, light gray, fine grained

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