Mounting LVM volumes differs from mounting "normal" partitions. This page might have some help: http://www.brandonhutchinson.com/Mou...VM_volume.html
Basically a LVM group is inside one partition, and in that LVM group there are several volumes (root, boot, home etc. which would usually be on different partitions). There are good and bad sides in using LVM, I personally try to avoid using it anywhere just because it's easier to deal with normal partitions in problematic situations.