To properly analyze the symbolism in this excerpt, we need to understand the overall theme, setting, and characters involved.
For example:
* What is the setting? Is it a battle scene, a dream sequence, a religious setting, etc.?
* Who are the "they" in the sentence? Are they humans, animals, spirits, etc.?
* What is the significance of "shades," "piercing howls," and "rolling weights" in the context of the story?
Once you provide more context, I can help you understand the intended use of symbolism in this excerpt.