This may be a no-brainer, but what
do you see in /mnt/us?
General comment: you should
really get used to providing relevant information. Just saying "it doesn't work" or "I don't see files" is
not sufficient to troubleshoot potential problems. You will greatly help yourself, as well as the ones who are trying to help you, by providing as detailed information as possible.
What did you do? What did you expect? And most importantly,
what did you try?(*)
(*) Thanks, geekmaster!