Published online by Cambridge University Press: 01 May 2009
The outlying mass of Lias on the borders of Shropshire and Cheshire is so thickly covered with Boulder-drift, that its line of boundary throughout almost its entire circumference is very obscure. The direct sequence from the underlying Keuper Marls is scarcely anywhere visible, and I believe no record of the occurrence of the Avicula contorta zone has hitherto been published.