Abstract

An analysis of the fauna of the Lower Cambrian Monkton Quartzite indicates the presence of 5 brachiopods, of which 3 are identified specifically; 1 unnamed new gastropod; 2 species of Hyolithes; and 6 species of trilobites, of which 5 are identified. All identified species occur in the lower Parker Slate or upper Dunham Dolomite of the St. Albans region. The fossil evidence demonstrates that the Monkton and the Parker are lateral facies of a once-continuous unit and that their present geographic separation is due to later erosion. All species are described. No new taxa are noted from the Monkton fauna, but the gastropod genus Scenella is considered and a new subgenus Protoconchoides, is proposed, as well as the new species Scenella (Protoconchoides) palmeri from the Lower Cambrian Pioche Shale at Eureka, Nevada. The classification of the Lower Cambrian ptychopariid trilobites is reexamined and 2 families, Antagmidae Hupe and the Eoptychopariidae, n. fam., are recognized. The Antagmidae contain 3 subfamilies, 6 genera, 2 named subgenera, and 22 assigned Lower Cambrian species. None of these taxa is new. The Eoptychopariidae contain 3 new subfamilies, Eoptychopariinae, Hadrokraspedinae, and Austinvilliinae; 5 genera, of which Hadrokraspedon is new; 2 subgenera, of which Cyphambon is new; and 16 species, none of which is new. Two genera and 4 species are noted whose classification is not determined.

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