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

Ineed to write a write a 4–5 paragraph compare and contrast essay that addresses how anne frank matures over the course of writing her diary.it's also a compare and contrast essayi just got put into this new class and i don't know if we were supposed to already be reading and the essay is due today and i haven't even started it nor read the book, someone me what do i do