What did the summer contain?

What did the summer contain?
(16)   It wasn't only the pine-scent, wasn't only
the meadow-sides flowing like a bright flag.
         At the river you picked up a
                                              handful of
         not only red river-gravel but all
            those one-syllable words: air, & love ...
(What dumb signposts they are! We who are tired
             of kicking up & down the same old road,
well, we have left some dents on them.)
         But, what was it?
Where the grass rippled up a bank,
         where we danced a mazurka & the
                                   sun became a golden berry -
what worm of no syllables
        lay wreathed & smiling in its gut?