To delete a range of ZFS snapshots, use the % (percent) character after the
full path to the first snapshot that should be included. For example, to
simulate deleting snapshots a through (including) d, use this command:

# zfs destroy -rvn mypool/tmp@a%d

Once you are sure that this is what you want, remove the -n option:

# zfs destroy -rv mypool/tmp@a%d

-- Benedict Reuschling <bcr@FreeBSD.org>