| Order | Type | Group | Form-ati | Member | Description | Upper | Lower | Basin |
| By No. | on | Age | Age |
| 3624.0 | SED | ORS | UIMD | Undifferentiated Interbedded Fm. | DM | SWAP |
| 3625.0 | AORS | Old Red Sandstone Unit A | D | CL | WESH |
| 3626.0 | BORS | Old Red Sandstone Unit B |
| 3627.0 | CORS | Old Red Sandstone Unit C |
| 3628.0 | DORS | Unit D |
| 3629.0 | EORS | Old Red Sandstone Unit E |
| 3630.0 | BUCH | Buchan Formation | SVIG CNSB |
| 3631.0 | UUOR | Old Red Sandstone Upper Unit | SVIG |
| 3632.0 | LUOR | Lower Unit |
| 3633.0 | DLMS | Late Devonian Marine Facies | DU | WLDB |
| 3634.0 | DILB | Ilfracombe Beds | DM |
| 3635.0 | UORS | Upper Old Red Sandstone | DF | CT | MOFI CNSB |
| 3636.0 | FICF | Firth Coal Formation | CL | CNSB |
| 3637.0 | URSE | Upper Old Red Sandstone Equiv | DA | WSXB |
| 3638.0 | ROSE | Rosebrae Beds | DF | HAPL EORB GRSP |
| 3639.0 | SCAT | Scatt Craig Beds |
| 3640.0 | ALVS | Alves Beds |
| 3641.0 | BOGS | Boghole and Whitemire Beds | DC | DF |
| 3642.0 | MORS | Middle Old Red Sandstone | MOFI |
| 3643.0 | CAFE | Caithness Flags Equivalent | DI | DV |
| 3644.0 | UPCO | Upper Conglomerate | DM |
| 3645.0 | LRCO | Lower Conglomerate |
| 3646.0 | MSF | Mid Sand Formation |
| 3647.0 | MDVS | Shale Unit | CNSB |
| 3648.0 | NARN | Nairn Sandstone | DC | HAPL EORB GRSP |
| 3649.0 | LORS | Lower Old Red Sandstone | DT | DB | MOFI |
| 3650.0 | SOSB | Strathpeffer, Ord and Spa Beds | DE |
| 3651.0 | RSE | Rhynie Sequence Equivalent | DS | INMF |
| 3652.0 | BRG | Brownstone Group | DB | WEL |
| 3653.0 | SENB | Senni Beds |
| 3654.0 | SMG | St Maughans Group | DT |
| 3655.0 | RAGL | Raglan Marl | SO |
| 3656.0 | PSLS | Psammosteus Limestone |
| 3657.0 | LORE | Lower Old Red Sandstone Lavas | DL | MID |
| 3658.0 | SMSL | Slate Mudstone Sst and Limestone | DU | WCHB |
| 3659.0 | PLYM | Plymouth Limestone | DM |
| 3660.0 | CALS | Calceola Shales |
| 3661.0 | STAD | Staddon Grits | DE |
| 3662.0 | MEAD | Meadfoot Beds | DS |
| 3663.0 | DART | Dartmouth Slates | DG |
| 3664.0 | DCON | Devonian Conglomerate Formation | D | MOFI |
| 3665.0 | CLAR | Clair Group | WESH |
| 3666.0 | UCLR | Upper Clair Group | C |
| 3667.0 | UC10 | Upper Clair Unit X |
| 3668.0 | UC9 | Upper Clair Unit IX |
| 3669.0 | UC8 | Upper Clair Unit VIII |
| 3670.0 | UC7B | Upper Clair VII B Formation | C | RWOR |
| 3671.0 | UC7A | Upper Clair VII A Formation |
| 3672.0 | LCLR | Lower Clair Group | D |
| 3673.0 | LCVI | Lower Clair VI Formation |
| 3674.0 | ULC6 | Upper Unit VI | WESH |
| 3675.0 | LCVV | Lower Clair V Formation | RWOR |
| 3676.0 | LCIV | Lower Clair IV Formation |
| 3677.0 | LC3 | Lower Clair Unit III | WESH |
| 3678.0 | SUND | Undifferentiated Group (Silurian | S | CHE |
| 3679.0 | LWG | Ludlow - Wenlock Group |
| 3680.0 | WEL | Wenlock Limestone |
| 3681.0 | WESH | Wenlock Shale |
| 3682.0 | LUSH | Ludlow Shale |
| 3683.0 | DCG | Downton Castle Group | SU | WEL |
| 3684.0 | WHIB | Whitcliffe Beds |
| 3685.0 | LEIN | Leintwardine Beds |
| 3686.0 | INGE | Bringewood Beds |
| Page 59 of 60 | 07/07/2004 |