What is the meaning of the simile “a bright girdle” in this excerpt from “dover beach” by matthew arnold?

the sea of faith
was once, too, at the full, and round earth's shore
lay like the folds of a bright girdle furled.
but now i only hear
its melancholy, long, withdrawing roar,
retreating, to the breath

Which statement best describes the use of the underlined word in the excerpts? in excerpt 1, it refers to personal growth, while in excerpt 2, it suggests the physical act of moving. in excerpt 1, it refers to personal growth, while in excerpt 2, it suggests scientific discoveries. in excerpt 1, it refers to societal advancement, while in excerpt 2, it suggests the gradual march of time. in excerpt 1, it refers to societal advancement, while in excerpt 2, it suggests steps toward a particular goal.