Mail files have disappeared with Lion upgrade

I have successfully applied Lion to my IMAC
I have now applied Lion to my macbook
Oddly my Mail & Mail Downloads files normally held in the Library folder have vanished
They must be there because everything shows when using Mail
I did a search and found the files listed under MacHD - Users - myname - library
BUT when you actually go into that directory they are simply not listed
I have gone back found them and copied them onto my desktop just in case
But where are they? Looks like they are hidden for some reason...
How do you make them visible?
Many thanks indeed!
Gary

The Library file is not shown by default in Lion.

There's a library file in the root of your Mac HD.... may be a silly question but are you sure you're not just looking in the wrong place?