Cosheston Group

{{Short description|Geological group in west Wales}}

{{Infobox rockunit

| name = Cosheston Group

| image =

| caption =

| type = Group

| age = Lochkovian to Emsian (Devonian)

| period = Early Devonian

| prilithology = sandstones, siltstones

| otherlithology = conglomerates

| namedfor = Cosheston

| namedby =

| region =

| country = Wales

| coordinates =

| unitof = Old Red Sandstone Supergroup

| subunits = New Shipping Formation, Lawrenny Cliff Formation, Mill Bay Formation, Burton Cliff Formation, Llanstadwell Formation

| underlies = Avon Group (unconformity)

| overlies = Gelliswick Bay Formation

| thickness = up to 1800m

| extent = south Pembrokeshire

| area =

| map =

| map_caption =

}}

The Cosheston Group is an early Devonian lithostratigraphic group (a sequence of rock strata) in west Wales. The name is derived from the village of Cosheston in south Pembrokeshire. The Group comprises (in ascending order) the Llanstadwell, Burton Cliff, Mill Bay, Lawrenny Cliff and New Shipping formations. The strata are exposed in the Milford Haven area of southern Pembrokeshire where several partial type sections are defined. The outcrop extends around the northern and southern shores of the Haven. It is bounded to the north by the Benton Fault between the villages of Rosemarket and Lawrenny, and extends east to New Shipping and west almost to the town of Milford Haven itself.British Geological Survey 1:50,000 scale geological map (England & Wales) sheet 228 Haverfordwest The rocks of this group have also previously been known as the Cosheston Beds.http://www.bgs.ac.uk/Lexicon/lexicon.cfm?pub=COB (BGS on-line lexicon of rock units)