A speaker walks along a shore early in the morning, and the day feels slightly off. Calling the morning "a counterfeit bill" suggests something that looks real but can't quite be trusted, perhaps a pale, false light or a mood that doesn't ring true. Then the poem turns on the word "but": the sea, whatever else is fake, is simply itself.
The middle image is the strangest. "A dozen white gloves" playing cards could be waves breaking into foam, or gulls or shells scattered on the sand. Judging by the imagery, they go "quiet," as if the game has paused. The picture is playful and a little eerie, with hands but no people.
In the final lines the speaker stops trying to read the scene and just walks, "attending the talk of water." The word "attending" suggests careful, respectful listening. The mood is calm and attentive, with a faint unease that the sea gently dissolves.