Published online by Cambridge University Press: 14 July 2015
Colonial rugose corals are uncommon in Pennsylvanian rocks in North America and until now the only massive form known from rocks of this age south of the Arctic is an undescribed species of Petalaxis reported by Sutherland (1985) from Morrowan rocks in Oklahoma, Texas, and New Mexico. This report concerns a second species of Petalaxis recovered from Desmoinesian rocks immediately west of Death Valley, California. Although only a single colony has been found, it is profoundly different from all other described species of this genus and is significant from the standpoint of its presence during a very long time span when there was an apparent dearth of massive rugose corals in most of North America.