U.S. Geological Survey Circular 946, p. 29-33. 6. MASSIVE MUDSTONES IN BASIN ANALYSIS AND PALEOCLIMATIC INTERPRETATION OF THE NEWARK

Massive red or gray mudstones make up much of the fine-grained sedimentary rocks of the Newark Supergroup. In fact, the upper third of most sedimentary cycles in the fine-grained facies of most Newark basins is massive mudstone (division 3 of Olsen, 1984). Massive mudstones have not, however, been studied or described nearly as fully as conglomerates, sandstones, and laminated shales. This lack is due primarily to the difficulty in making textural descriptions from weathered outcrop exposures of massive mudstones and to the dearth of published depositional models for them. The widespread distribution and fades associations of massive mudstones in the early Mesozoic basins sug-