Numerous faults trend north-south through the basin, some of which help to define the series of hills which are known collectively as the Mid Cheshire Ridge.
The basin was flooded on several occasions in the Permian and early Triassic periods resulting in the laying down of massive halite (salt) beds.
Rocks of Permian age occur to the west of Chester and in restricted areas to the southeast and northeast of the city, although again largely obscured by superficial deposits.
The larger part of the Cheshire Plain is covered by a thick mantle of glacial till and sands and gravels of glacio-fluvial origin.
The present distribution of deposits and the landforms to which they give rise are largely the result of the last ice age, the Devensian which peaked around 22-20,000 years ago.
The morphology of both the Dee and Mersey estuaries is in large part owed to the passage of Irish Sea Ice southwestwards over the relatively soft sandstones of the area.
A considerable number of small glacial meltwater channels have been identified along the Mid Cheshire Ridge such as that known as Urchin's Kitchen near Kelsall whilst larger examples occur along the edges of the Peak District.