These Triassic rocks, which are chiefly sandstones, hold no marine
fossils, and hence were not laid in open arms of the sea. But
their layers are often ripple-marked, and contain many tracks of
reptiles, imprints of raindrops, and some fossil wood, while an
occasional bed of shale is filled with the remains of fishes. We
may conceive, then, of the Connecticut valley and the larger
trough to the southwest as basins gradually sinking at a rate
perhaps no faster than that of the New Jersey coast to-day, and as
gradually aggraded by streams from the neighboring uplands. Their
broad, sandy flats were overflowed by wandering streams, and when
subsidence gained on deposition shallow lakes overspread the
alluvial plains. Perhaps now and then the basins became long,
brackish estuaries, whose low shores were swept by the incoming
tide and were in turn left bare at its retreat to receive the rain
prints of passing showers and the tracks of the troops of reptiles
which inhabited these valleys.

The Triassic rocks are mainly red sandstones,--often feldspathic,
or arkose, with some conglomerates and shales. Considering the
large amount of feldspathic material in these rocks, do you infer
that they were derived from the adjacent crystalline and
metamorphic rocks of the oldland of Appalachia, or from the
sedimentary Paleozoic rocks which had been folded into mountains
during the Appalachian deformation? If from the former, was the
drainage of the northern Appalachian mountain region then, as now,
eastward and southeastward toward the Atlantic? The Triassic
sandstones are voluminous, measuring at least a mile in thickness,
and are largely of coarse waste. What do you infer as to the
height of the lands from which the waste was shed, or the
direction of the oscillation which they were then undergoing? In