  In this paper, a system of one-dimensional gas dynamics equations is
considered. This system is a particular case of Jacobi type systems and has a
natural representation in terms of 2-forms on 0-jet space. We use this
observation to find a new class of multivalued solutions for an arbitrary
thermodynamic state model and discuss singularities of their projections to the
space of independent variables for the case of an ideal gas. Caustics and
discontinuity lines are found.
