The Ascog Member is part of the Clyde Sandstone Formation.
From Ascog, Isle of Bute. The member was defined by Paterson and Hall (1986).
Red-brown siltstone and sandstone with pedogenic limestone.
The type section occurs in the BGS Ascog Borehole (BGS Registration Number NS06SE/8) (NS 0986 6302) from 133.6 to 219.8 m depth.
Lower and upper boundaries
At the lower boundary, sandstone of the Ascog Member is interbedded with grey mudstone and dolomitic limestone (‘cementstone’) of the Ballagan Formation. The boundary is picked where beds of dolomitic limestone (‘cementstone’) are absent and sandstone becomes the predominant lithology.
At the upper boundary there is a sharp change at the probably erosional base of the overlying Birgidale Formation, which comprises mudstone, sandstone, seatrock and coal.
Some 86.m. However, BGS (2008) gave a generalised thickness of 75.m for the member on the Isle of Bute.
Distribution and regional correlation
Isle of Bute, Strathclyde.