Detailed investigation of the Blue Lias beds in Dorset, Somerset (England), and Glamorgan (Wales) has revealed evidence of the primary origin of the rhythmic banding. This consists of the presence of barren interstratified paper shales and U-shaped burrows of worms, and the constant thickness of the beds over distances of many miles. Kent indicates that this evidence is not well supported where the beds have been examined in the Midlands.

You do not currently have access to this article.