Many thin sandstone units are graded, and locally display starved ripples with shapes and internal cross-laminations indicating the sense of current transport. Scattered through the section are rounded pebbles up to 6 cm in diameter...which occur within thicker mudstone layers as well as on bedding planes demarcated by graded sandstones". Occasional pockets of such pebbles were observed by Sussmilch. Glaessner (1957) described and illustrated a new species of arthropod trace fossil, Isododichnus osbornei, from varve shales at Seaham. The exact locality is not stated but the specimens were most likely collected from the quarry where they had previously been recorded as annelid tracks. The probable depositional environment of the quarry strata, as envisaged by Rattigan (1967) and other workers, was a shallow periglacial lake which received sediment influxes via turbidity currents. Low velocity traction currents modified the surface of these lake bed deposits, and ice-rafted pebbles (derived from moraines) were dropped into them at intervals from melting floes and icebergs. Crowell and Frakes (1971) consider that this glaciation was of alpine type and took place at a (late Carboniferous) latitude of 45-50 degree S. Perhaps the most spectacular features exposed in the quarry are localised contorted beds interstratified between apparently undisturbed layers and laterally continuous with undeformed planar strata. The height of the contorted layers ranges from a few centimetres to a metre or more. In Edgeworth David's day, the cause of the deformation was thought to be "the dragging force of glacial ice or icebergs". However Fairbridge (1947), who reviewed in detail seven possible explanations of the origin of the contortions, concluded that ravitational slumping - probably due to release of water from impounded glacial lakes, or over loading, was the most likely cause. Subsequent investigators considered that some of the contorted layers could equally well have resulted from grounding of icebergs and floes. Rattigan (1967) described a variety of other deformational phenomena from these strata, including lode and flow structures, intraformational facturing, penecontemporaneous sand intrusions, and non-hydrodynamic ripple forms. He proposed earthquake-activated slumping as a possible mechanism of formation. The other feature of the strata exposed in the quarry which has attracted scientific interest is the significance of the laminations.