  We define and characterize the $\gamma$-matrix associated to Pascal-like
matrices that are defined by ordinary and exponential Riordan arrays. We also
define and characterize the $\gamma$-matrix of the reversions of these
triangles, in the case of ordinary Riordan arrays. We are led to the
$\gamma$-matrices of a one-parameter family of generalized Narayana triangles.
Thus these matrices generalize the matrix of $\gamma$-vectors of the
associahedron. The principal tools used are the bivariate generating functions
of the triangles and Jacobi continued fractions.
