  We use a cluster algorithm to study the critical behavior of strongly coupled
lattice QCD in the chiral limit. We show that the finite temperature chiral
phase transition belongs to the O(2) universality class as expected. When we
compute the finite size effects of the chiral susceptibility in the low
temperature phase close to the transition, we find clear evidence for chiral
singularities predicted by chiral perturbation theory (ChPT). On the other hand
it is difficult to reconcile the quark mass dependence of various quantities
near the chiral limit with ChPT.
