First Known When Lost: "I Clutch The Memory Still, And I Have Measured Everything With It Since"

First Known When Lost: "I Clutch The Memory Still, And I Have Measured Everything With It Since"
Excerpt:
"The Peninsula," which ends with the following stanza:

And drive back home, still with nothing to say
Except that now you will uncode all landscapes
By this: things founded clean on their own shapes,
Water and ground in their extremity.
Seamus Heaney, Door into the Dark (1969).
...
Conceived beyond such innocence,
I clutch the memory still, and I
Have measured everything with it since.
Derek Mahon