Correlation of the Early Mesozoic Newark Supergroup by Vertebrates, Principally Fishes

New data on the distribution of fossil fish together with floral and tetrapod evidence are used to develop an internal correlation of the strata of the early Mesozoic Newark Supergroup of eastern North America. Within the Newark, we recognize five informal biostratigraphic zones, each characterized by a particular fish fauna. These fish zones are then related to other Mesozoic freshwater deposits, augmented by palynologic and tetrapod data, to the European type area, and to important Early Mesozoic terrestrial sequences elsewhere. The oldest fish zones are the Dictyopyge zone found in the Middle Carnian age rocks of the Richmond, Taylorsville, and Scottsburg Basins and the Middle and Late Carnian Diplurns newarki zone represented in the -ham group, Dan River Group, Gettysburg Basin, and Newark Basin. These two zones correlate with the Chinle Formation and the Dockum Group of the southwestern United States as well as the Middle and Late Carnian rocks of the German basin. *The three youngest zones, early Jurassic in age, are characterized primarily by species groups of the holostean Semionotus. Fishes of the "Semionotus tenuiceps group" zone are known from the Hettangian Feltville and Towaco Formations of the Newark Basin and the Turners Falls Sandstone of the Deerfield Basin. The "Semionotus micropterus group" zone is found in the Late Hettangian-Early Sinemurian rocks of the Shuttle Meadow and East Berlin Formations of the Hartford Basin and the "Midland fish bed" of the Culpeper Basin. Youngest of these semionotid zones is the Sinemurian "Semionotus elegans group" representatives of which occur in the Sinemurian Portland Formation of the Hartford Basin and the Boonton Formation of the Newark Basin. Correlation by these fish zones suggests that all the coal-bearing Newark rocks are divisible into an older and younger sequence both dated palynologically (by others) as Middle Carnian. Further, while the time span over which extrusive basalts were deposited is limited to the Hettangian and Sinemurian of the Early Jurassic, the individual basalt flow formations are not correlative among basins in a simple one to one manner according to the biostratigraphic data. With respect to the rest of the world, the "Semionotus tenuiceps group," "S. micropterus group," and the "S. elegans group" zones correlate with the European Early Jurassic, the Glen Canyon Group of the southwestern United States, the upper . Stormberg Group of southern Africa, and the Lower Lufeng of China. 1 Fig. 1. The Newark Supergroup of eastern North America: (1) Wadesboro Basin (Chatham Group), (2) Sanford Basin (Chatham Group), (3) Durham Basin (Chatham Group), (4) Davie County Basin, (5) Dan River and Danville Basins (Dan River Group), (6) Scottsburg Basin, (7) basins south of the Farmville Basin, (8) Farmville Basin, (9) Richmond Basin, (10) Taylorsville Basin, (11) Scottsville Basin, (12) Culpeper Basin, (13) Gettysburg Basin, (14) Newark Basin, (15) Pomperaug Basin, (16) Hartford Basin and Cherry Brook outlier, (17) Deerfield Basin, (18) Fundy Basin (Fundy Group), (19) Chedabucto Basin (? Orpheus Graben). Data primarily from Calver (1963). Jansa and Wade (1975). King and others (1944), Van Houten (1977). and Olsen (1978).