  We study hierarchies of replica-symmetry-breaking solutions of the
Sherrington-Kirkpatrick model. Stationarity equations for order parameters of
solutions with an arbitrary number of hierarchies are set and the limit to
infinite number of hierarchical levels is discussed. In particular, we
demonstrate how the continuous replica-symmetry breaking scheme of Parisi
emerges and how the limit to infinite-many hierarchies leads to equations for
the order-parameter function of the continuous solution. The general analysis
is accompanied by an explicit asymptotic solution near the de Almeida-Thouless
instability line in the nonzero magnetic field.
