ubuntu - How to disable software raid (mdadm)?

I have two 500GB hard disk that were in a software RAID1 on a gentoo distribution. Now I have put the on an Ubuntu Server 10.10 and they still want to be in a RAID. How do I disable the RAID.

sudo mdadm --detail /dev/dm-1
mdadm: /dev/dm-1 does not appear to be an md device

sudo mdadm --stop /dev/dm-1
mdadm: /dev/dm-1 does not appear to be an md device

Device Boot Start End
Blocks Id System /dev/sdb1
1 60801 488384001 83 Linux

Disk /dev/sdd: 500.1 GB, 500107862016

bytes 255 heads, 63 sectors/track,
60801 cylinders Units = cylinders of
16065 * 512 = 8225280 bytes Sector
size (logical/physical): 512 bytes /
512 bytes I/O size (minimum/optimal):
512 bytes / 512 bytes Disk identifier:
0x00000000

Device Boot Start End
Blocks Id System /dev/sdd1
1 60801 488384001 83 Linux

Disk /dev/sdc: 500.1 GB, 500107862016
bytes 255 heads, 63 sectors/track,
60801 cylinders Units = cylinders of
16065 * 512 = 8225280 bytes Sector
size (logical/physical): 512 bytes /
512 bytes I/O size (minimum/optimal):
512 bytes / 512 bytes Disk identifier:
0x00000000

Device Boot Start End
Blocks Id System /dev/sdc1
1 60801 488384001 83 Linux

Disk /dev/dm-1: 500.0 GB, 499999965184
bytes 255 heads, 63 sectors/track,
60788 cylinders Units = cylinders of
16065 * 512 = 8225280 bytes Sector
size (logical/physical): 512 bytes /
512 bytes I/O size (minimum/optimal):
512 bytes / 512 bytes Disk identifier:

0x00000000

 Device Boot      Start         End      Blocks   Id  System

/dev/dm-1p1 1
60801 488384001 83 Linux