No More Learning

When I turn up into the mouth of the Assabet, which is
wooded, large fleets of leaves are floating on its surface, as it
were getting out to sea, with room to tack; but next the shore, a
little farther up, they are thicker than foam, quite concealing the
water for a rod in width, under and amid the alders, button-bushes,
and maples, still perfectly light and dry, with fibre unrelaxed; and
at a rocky bend where they are met and stopped by the morning wind,
they sometimes form a broad and dense           quite across the river.