Article: Brachipod distributions and the faunal provinces in the Silurian and Lower Devonian

Silurian shelf faunas were cosmopolitan, except for two areas: (i) South America and west Africa yield the Clarkeia fauna from the Llandovery to the Ludlow; and (ii) north-westem America, north Greenland, and the U.S.S.R. yield the Atrypella fauna in the Late Silurian. During the Lower Devonian several provinces gradually appeared, to reach five in number by Emsian time. The geographical extent and composition of these provinces varies with time, and the distribution of the faunas is related to palaeolatitude, presumably reflecting climatic zones

Faunal links between northern North America and the U.S.S.R. east of the Urals suggest proximity between these land masses in the Late Silurian and Early Devonian