Second Contribution to the Studies on the Cambrian Faunas of North America

Agnostus Amer apex axial lobe axis Bathyuriscus beak Bic Harbor Billings Cañon characters Collection U. S. National convex Crepicephalus dorsal furrows dorsal valve elongate Emmons enlarged Eureka facial suture Fixed cheeks Formation and localities.-Middle Formation and locality.-Middle Foss fossils free cheeks front frontal limb genera genus Georgia Formation glabella groove head Highgate Springs horizon Hyolithes Idem interior Jour Kutorgina L'Anse au Loup lateral lobes length limestone lines Lingulella localities.-Middle Cambrian locality.-Middle Cambrian Microdiscus Middle Cambrian narrow nearly Nevada Obolella occipital ocular ridge Olenellus Olenellus Gilberti Olenoides Olenus operculum Paradoxides Plate pleuræ pleural lobes posterior margin Potsdam Ptychoparia pygidium quartzite rounded S. W. Ford sandstone scars Scenella segments septa shales shell side Silurian slightly species spines Stenotheca surface Taconic thorax transverse trilobite Troy type specimen U. S. Geol U. S. National Museum Upper Cambrian ventral valve Vermont Walcott width