The Rough Rock is a widespread unit of coarse sandstone

Sandstone

Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...

 which is a prominent landscape-forming feature in the Peak District

Peak District

The Peak District is an upland area in central and northern England, lying mainly in northern Derbyshire, but also covering parts of Cheshire, Greater Manchester, Staffordshire, and South and West Yorkshire....

 and Pennines

Pennines

The Pennines are a low-rising mountain range, separating the North West of England from Yorkshire and the North East.Often described as the "backbone of England", they form a more-or-less continuous range stretching from the Peak District in Derbyshire, around the northern and eastern edges of...

 of northern England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

. It is assigned by geologists to the Yeadonian sub-stage of the 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...

 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.

It is the most extensive of all of the sandstones of the Millstone Grit Group

Millstone Grit

Millstone Grit is the name given to any of a number of coarse-grained sandstones of Carboniferous age which occur in the Northern England. The name derives from its use in earlier times as a source of millstones for use principally in watermills...

 occurring throughout the Peak District

Peak District

The Peak District is an upland area in central and northern England, lying mainly in northern Derbyshire, but also covering parts of Cheshire, Greater Manchester, Staffordshire, and South and West Yorkshire....

, South

South Pennines

South Pennines is a region of moorland and hill country in northern England lying towards the southern end of the Pennines. It is bounded to the west by the Forest of Rossendale and the Yorkshire Dales to the north...

 and West Pennines

West Pennine Moors

The West Pennine Moors cover an area of approximately of moorland and reservoirs in Lancashire and Greater Manchester, England.The West Pennine Moors are separated from the main Pennine range by the Irwell Valley. The moorland includes Withnell, Anglezarke and Rivington Moors in the extreme west,...

 and extending northwards into the central and northern Pennines.

It originated as a sheet of deltaic deposits

River delta

A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...

 spread across most of 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...

associated with major rivers flowing from the north and northeast.