rustling from

[Mher]

What does the author mean by "rustling from"?
"But, alas! the real sleepers were fewer, by many millions, than those who slumbered not at all; and there was a feeble struggling; andthere was a general sad unrest; and from out the depths of the countless pits there came a melancholy rustling from the garments of the buried."

 

[Tdol]

I assume it refers to the noise that garments would make when being rubbed or moved.

 

[Mher]

I assume it refers to the noise that garments would make when being rubbed or moved.

I guess, "melancholy" here is used as an adjective.
And what do you think about "not at all"? Is it something like "not completely"?

 

[Mrfatso]

In this context I think "not at all" means that the persons in question did not sleep, for some reason they had insomnia.