  We study early universe cosmologies derived from a scalar-tensor action
containing cosmological constant terms and massless fields. The governing
equations can be written as a dynamical system which contains no past or future
asymptotic equilibrium states (i.e. no sources nor sinks). This leads to
dynamics with very interesting mathematical behaviour such as the existence of
heteroclinic cycles. The corresponding cosmologies have novel characteristics,
including cyclical and bouncing behaviour possibly indicating chaos. We discuss
the connection between these early universe cosmologies and those derived from
the low-energy string effective action.
