The Coal Measures Group is a lithostratigraphical

Lithostratigraphy

Lithostratigraphy is a sub-discipline of stratigraphy, the geological science associated with the study of strata or rock layers. Major focuses include geochronology, comparative geology, and petrology...

 term

Group (stratigraphy)

A group in stratigraphy is a lithostratigraphic unit, a part of the geologic record or rock column that consists of defined rock strata. Groups are divided into formations and are sometimes themselves grouped into "supergroups"....

 coined to refer to the coal

Coal

Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...

-bearing succession of rock strata

Stratum

In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers...

 which occur in Great Britain

Great Britain

Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...

 within the Westphalian

Westphalian

Westphalian may refer to:* The culture or people of the Westphalia region of Germany* Westphalian language, one of the major dialect groups of West Low German* Westphalian sovereignty, a concept in international relations* Westphalian , in geology...

 Stage of the Carboniferous

Carboniferous

The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...

 Period. The Coal Measures Group is preceded (underlain) by the Millstone Grit Group which is of Namurian

Namurian

The Namurian is a stage in the regional stratigraphy of northwest Europe with an age between roughly 326 and 313 Ma . It is a subdivision of the Carboniferous system or period and the regional Silesian series. The Namurian is named for the Belgian city and province of Namur where strata of this age...

 age. It is succeeded (overlain) by the Warwickshire Group

Warwickshire Group

The Warwickshire Group is a lithostratigraphic unit of rock strata defined within the British Carboniferous system. Within the Pennine Basin it overlies the Coal Measures Group and is deemed to be of late Westphalian and Stephanian age...

 which comprises a largely non-productive sequence of red beds. Within the Pennine Basin

Pennine Basin

The Pennine Basin is a sedimentary basin which was active during the Carboniferous Period and which reached from the Southern Uplands of Scotland in the north to the former Wales-London-Brabant Massif in the English Midlands to the south...

 it comprises the:

• Upper Coal Measures Formation
• Middle Coal Measures Formation
• Lower Coal Measures Formation

The 'Pennine Basin' includes all of the coalfield

Coalfield

A coalfield is an area of certain uniform characteristics where coal is mined. The criteria for determining the approximate boundary of a coalfield are geographical and cultural, in addition to geological...

s of northern England and the English Midlands

English Midlands

The Midlands, or the English Midlands, is the traditional name for the area comprising central England that broadly corresponds to the early medieval Kingdom of Mercia. It borders Southern England, Northern England, East Anglia and Wales. Its largest city is Birmingham, and it was an important...

 together with the Canonbie Coalfield

Canonbie Coalfield

The Canonbie Coalfield is a small and largely concealed coalfield at Canonbie in the south of Scotland. Survey work in recent years revealed potentially economically workable reserves beneath a cover of New Red Sandstone rocks...

 of southern Scotland and the coalfields of northeast Wales

North Wales Coalfield

The North Wales Coalfield comprises the Flintshire Coalfield in the north and the Denbighshire Coalfield in the south. It extends from Point of Ayr in the north, through the Wrexham area to Oswestry in Shropshire in the south....

 and Anglesey

Anglesey Coalfield

The Anglesey Coalfield is a minor British coalfield. Situated in north-west Wales, it is not usually considered to form a part of the North Wales Coalfield which lies in Flintshire and Denbighshire in north-east Wales. Stretching from the Gaerwen area to Malltraeth, it is around 9 miles long....

.

A similar scheme operates in the Midland Valley Basin of Scotland

Scotland

Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

. In those coalfields to the south of the former Wales-Brabant High ie the South Wales

South Wales Coalfield

The South Wales Coalfield is a large region of south Wales that is rich with coal deposits, especially the South Wales Valleys.-The coalfield area:...

, Bristol

Bristol Coalfield

The Bristol Coalfield is a geologically complex coalfield in the west of England. Comprising the coal-bearing rocks arranged around the Coalpit Heath Syncline and Kingsdown Anticline, it extends beneath the eastern parts of the city of Bristol and northwards through southern Gloucestershire...

, Somerset

Somerset coalfield

The Somerset Coalfield included pits in the North Somerset, England, area where coal was mined from the 15th century until 1973.It is part of a wider coalfield which covered northern Somerset and southern Gloucestershire. It stretched from Cromhall in the north to the Mendip Hills in the south, and...

 and Forest of Dean

Forest of Dean Coalfield

The Forest of Dean Coalfield, lying under the Forest of Dean, in northwest Gloucestershire, is one of the smaller coalfields in the British Isles, although intensive mining during the 19th and 20th centuries has had enormous influence on the landscape, history, culture and economy of the area.For...

 Coalfields, the corresponding group is the South Wales Coal Measures Group. It comprises the:

• Middle Coal Measures Formation
• Lower Coal Measures Formation

In South Wales, the Upper Coal Measures Formation is grouped with the Pennant Sandstone Formation in the overlying Warwickshire Group. The South Wales Coal Measures Group is preceded (underlain) by the Marros Group

Marros Group

The Marros Group is the name given to a suite of rocks of Namurian age laid down during the Carboniferous period in South Wales. These rocks were formerly known as the Millstone Grit Series but are now distinguished from the similar but geographically separate rock sequences of the Pennines and...

.