Preliminary report on the stratigraphy of Cretaceous strata exposed in the Aston Clinton Bypass (A 41) excavations

This report gives a preliminary account of the stratigraphy of the Chalk Group of the Aston Clinton Bypass (A41) visible during construction work in August 2002. Exposures of the topmost Gault and Upper Greensand are also briefly described. The vertical thickness of the Chalk Group exposed along the length of the excavation is difficult to determine because of poor exposure of individual beds, variable dip, and likely repetition of strata by faulting. However, preliminary interpretations for the Grey Chalk Subgroup suggest that it may be similar in thickness and stratigraphical development to the succession recorded at Pitstone Quarry [SP 946 147] (Mortimore et al., 2001), c. 6 km to the north-east of the construction site.