I've seen pieces of matrix with etched out, reddish corals, listed as being from the Devonian near Payson, AZ, on E-bay for a while now. I was able to acquire the specimen below for my collection from a local dealer not long ago. I don't know too much about the formation, stage or species found but there seems to have been a healthy reef at some point.
Based on what I know about Devonian corals and bryozoans I can pick out a few genera like Cladopora sp., Aulocystis sp., Striatopora sp. and Thamnopytchia sp.