Stratigraphy and primary sedimentary structures of fine-grained, well-bedded strata, inferred lake deposits, upper Triassic, central and southern Connecticut

Upper Triassic strata and lava that filled a subsiding N-S fault trough were tilted eastward, folded, and faulted prior to Late Cretaceous time. Coarse-grained fan deposits are along the eastern margin; fine-grained, well-bedded deposits, with basalt layers, are more distant. Most of them are red flood-plain deposits; some are intercalated with gray lake beds and black swamp deposits. Near Branford the fine-grained strata are in two formations, at localities within 1 km of the eastern fault, where younger and older strata are coarse conglomerates. Two separate large, deep lakes submerged the alluvial fans high up on the escarpment, but when not so high allowed uninterrupted alluvial fan deposition. Paleocurrent indicators were diversely oriented by lake bottom topography. Pillows and volcanic breccia resulted when hot lava hit cold lake water.