Stratigraphy and Structures East of Oxford

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Abstract
I. I ntroduction T he Geological Survey 1-inch map of Oxford (1908) shows to the east of the city a remarkable belt of faults, running from north-west to southeast for 12 miles and passing at its nearest point within three miles of Magdalen Bridge. Starting in the Great Oolite and Forest Marble of Islip, the faults cut through the Corallian rocks between Elsfield and Beckley and bound the Corallian limestones of Wheatley. They also shift the Kimeridge Clay, Portland Beds and Shotover Sands of Forest Hill, Great Milton and Great Haseley, as far as the margin of the overstepping Gault. Closer inspection of the map makes it clear that these are by no means simple faults. In fact, no satisfactory interpretation of the structure is possible from the arrangement of outcrops and faults shown on the map. The explanatory memoir (1908), by T. I. Pocock, H. B. Woodward, and G. W. Lamplugh, contains no chapter on structural geology. There are, however, scattered references to structure in the stratigraphical chapters, and these were reproduced without alteration in the second edition (Pringle 1926 1). The authors referred to trough-faulting with displacements of 200 feet and 80 feet, to step-faulting, and to a " general Hne of fracture and displacement " which " owing to the meagre field-evidence, could not be deciphered in detail ". No mention was made of folding, and for the most part the mapping shows that none was envisaged. In the light of experience gained in mapping other “lines of