The flow of time in the Connecticut valley : $b geological imprints — John Shaqi
The flow of time in the Connecticut valley : $b geological imprintsBain, George W. (George William)
Science
The flow of time in the Connecticut valley : $b geological imprints
Bain, George W. (George William)
Geology -- Connecticut River Valley
Near the northern terminus of the Triassic basin the eastern boundary
was not subject to intermittent and violent movements during the later
stages of sedimentation, as it was in the south. Instead, the youngest
part of the red-rock inlay consists, in some places, of unfractured
boulder beds which were washed far out towards the center of the
lowland; elsewhere, landslides brought masses of rock debris upon soft
red and gray shales, which may have accumulated in shallow lakes; in
still other localities, long stringers of red sediment reach far back
into the eastern highlands. Many boulders in the conglomerate at the
south end of Mount Toby are eight feet in diameter, and torrential
mountain streams brought them to their resting place. A few are
scratched and grooved, much like the boulders in the till left by the
ice sheet; perhaps they signify the presence of snow fields and glaciers
in the mountain range, but the scratches may have been acquired by
avalanching. The landslide masses buried in the shales at the Sunderland
caves show that the mountain front was steep, and the ancient talus or
slide rock near the Central Vermont Railroad south of Roaring Brook
shows plainly that the mountain front was a precipitous cliff of
granite. The stringers of conglomerate extending eastward into the
granite upland south of Montague, north of Leverett station, at Amherst,
and again near Granby, are alluvial fill in ancient mountain gorges.
This old mountain mass stood out as a long, straight range extending
from a point east of New Haven northward into New Hampshire. It was of
moderate height in Connecticut, but it became higher and more rugged to
the north; glaciers may have nestled around its crest east of Deerfield,
and its front was an impressive slope of slide rock. Granite gorges with
tapering gravel plains, dry one day and raging torrents the next,
fingered eastward into the mountain block. At that time the Connecticut
Valley was much like the land east of the Sierra Nevada in California,
where greater contrasts in heights and depths are to be found than in
any other part of the United States.
_A Dinosaur Diary_
Public-domain text, read in full here on John Shaqi.
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