When using the filesystem type that means auto-sense the FS,
the man page says to use "autofs" and "auto".  Given that
the use of "auto" produces this error:

bash$ mount /mnt/floppy
mount: you must specify the filesystem type

I suspect the correct type to use is "autofs".

The man page says:
       -t vfstype
              The  argument  following the -t is used to
indicate
              the file system type.  The file system types
which
              are    currently    supported    are
listed   in
              linux/fs/filesystems.c: minix,  xiafs,  ext,
ext2,
              msdos,  umsdos,  vfat,  proc,  autofs, devpts,
nfs,
------------------------------------------------^

and a little further down contradicts this:

              The  type  iso9660 is the default.  If no -t
option
              is given, or if the auto  type  is
specified,  the
------------------------------------^
              superblock   is  probed  for  the  filesystem
type
              (minix, ext, ext2, xiafs, iso9660, romfs  are
sup-
              ported).

AFAIK, the msdos and vfat FS types are also supported,
though this isn't mentioned either.

luke