howto mount another lvm partition on this one

[Paul S]

I have a gutsy installation with the /root as volg1-lvroot and swap as 
volg1-lvswap on the one partition, sda10.

I also have a 64 bit install on another partition, sda8, with the same 
designations (/root as volg1-lvroot and swap as volg1-lvswap).

I tried mounting the 32 bit partition on the 64 bit and just get an 
error message:

paul :~$ sudo mount /dev/mapper/sda10 /media/sda10
mount: unknown filesystem type 'LVM2_member'

same result if I try the reverse:

paul :~$ sudo mount /dev/mapper/sda8 /media/sda8
mount: unknown filesystem type 'LVM2_member'

What's the correct procedure to mount it?  I did a quick read of "man 
mount" but see nothing specific about lvm.  Also, in the  lvm-howto, I 
don't see anything about mounting other partitions that have lvm on them.

TIA