The Ammonite Succession at the Woodham Brick Company's Pit, Akeman Street Station, Buckinghamshire, and its bearing on the Classification of the Oxford Clay

Abstract

The Woodham Brick Company's pit was opened in 1936, about midway between Aylesbury and Bicester, on the north-east side of Akeman Street Station (L.N.E.R.). It lies four miles south-south-east of the brickfield in Kosmoceras Shales of the Lower Oxford Clay at Calvert Station, and 2¾ miles north-north-east of the G.W.R. cuttings at Rushbeds Wood, near Ludgershall, and between Ashendon and Dorton, where Upper Oxford Clay and Ampthill Clay were recorded (Davies 1916). Some of the railway-cuttings appear to have exposed almost the same beds as are now displayed at the Woodham pit, but they were partly sloped before examination, and no description of the succession or faunas was published. The brick-pit now described, therefore, is the first extensive exposure of the middle and the lower part of the Upper Oxford Clay in middle England from which fossils have been collected bed by bed. Its interest is exceptional, owing to the great abundance of well-preserved ammonites, of which up to the present more than 1250 specimens, belonging to 70 species, have been collected. Many species known hitherto only from the Hackness Rock of Yorkshire, or from the Oxford Clay of Dorset, France, or the Jura Mountains, occur here in association; and it has been possible to determine the horizons of nearly all of them. The material is used as the basis for the first attempt at a review of British Oxford Clay ammonites. The pit is at present (1938) about 70 feet deep, in nearly flat-lying beds. The highest 19 feet