  We show that a stack of metal-dielectric nanolayers, in addition to the long-
and short-range plasmons, guides also an entire family of modes strongly
confined within the multilayer - the bulk plasmon modes. We propose the
classification scheme that reflects specific properties of these modes. We
report experimental verification of the bulk plasmon modes by measuring modal
indices in a structure made of three pairs of silica(29nm)/gold(25nm) layers.
