The basal Gault and Gault-Woburn Sands junction beds in Chamberlain's Barn quarry, Leighton Buzzard, Bedfordshire, England

Southerly extension of the Chamberlain's Barn sand quarry north of Leighton Buzzard, Bedfordshire, has exposed sections showing the variability of the Gault-Woburn Sands junction beds, both in lithology and fauna. A Cleoniceras (Cleoniceras) floridum Subzone age had been established for the basal beds with a reworked mixed Leymeriella (Neoleymerielld) regularis and Sonneratia (Sonneratia) chalensis pebble bed above. Recent work has shown, however, that later sediments of Douvilleiceras mammillatum Superzone age are present in the southern portion of the pit. The age of the Gault sediments between the Pseudosonneratia (Isohoplites) steinmanni and the Hoplites (Hoplites) spathi Subzones are now confirmed as belonging to the Lyelliceras lyelli Subzone.