  The Cosserat equations for equilibrium are derived by starting from the
action of the group of smooth functions with values in the Lie group of rigid
spatial motions on rigid frames in Euclidian space. The method of virtual work
is employed, instead of the method of action functionals, and is defined using
the methods of of jet manifolds. It is shown how the restriction to fundamental
forms (which define the dynamical state of the Cosserat object) that are
Euclidian is essential to obtaining the Cosserat equations.
