The Upper Ordovician (450-460 Ma) Chazy, Black River and Trenton groups of eastern North America record the tectonic activation of a passive carbonate platform.
Ziegler (geology, U. of Basel, Switzerland) provides an overview of the late Palaeozoic evolution of North America, Europe, the Arctic and North Africa in a pla
This eleventh edition was developed during the encyclopaedia's transition from a British to an American publication. Some of its articles were written by the be