New trilobites from the Silurian of north-east Greenland, with a note on trilobite faunas in pure limestones

A trilobite fauna of approximately Wenlock age from Kronprins Christians Land, north-east Greenland is described. The fauna occurs in a pure limestone and includes five new species of trilobites—Opoa adamsi gen. et sp. nov., Meroperix ataphrus gen. et sp. nov. (Scutelluidae); Selenoharpes loma sp. nov. (Harpidae); Chiozoon cowiei gen. et sp. nov., Hyrokybe pharanx gen. et sp. nov. (Cheiruridae); with goldillaenids (two types) and lichids (two types) which also probably represent new genera, but which are not named because of the small number of specimens known. Members of the Calymenidae, Odontopleuridae, Proetidae, Otarionidae, and Illaenidae also occur. Comparison of elements of this new fauna with Silurian trilobites already described is possible only in three cases, the harpid being similar to several Silurian members of the genus, Chiozoon having a representative species in the Upper Silurian of Tadzhikskaya, USSR, and Hyrokybe with a possible species from the Lower Devonian of the western Urals. The delimitation of the Scutelluidae and the position of the Goldillaeninae is discussed. The occurrence of the same trilobite families, or of different trilobite families with similar morphology, in pure limestones differing in age from Arenig to middle Devonian is noted.