We give a new generalization of the spt-function of G.E. Andrews, namely Sptj(n), and give its combinatorial interpretation in terms of successive lower-Durfee squares. We then generalize the higher order spt-function sptk(n), due to F.G. Garvan, to jsptk(n), thus providing a two-fold generalization of spt(n), and give its combinatorial interpretation.