On Faults in the Drift-gravel at Hitchin, Herts
J. W. Salter · Quarterly Journal of the Geological Society · 1866
At Hitchin there is an admirable section laid open by the deep cliff-cutting of the Great Northern Railway, which exhibits faults affecting both chalk and an old gravel which, thanks to the investigations of Mr. Seeley (in Cambridgeshire) and the independent research of Mr. Thomas McKenny Hughes (nearer Hertford), I am enabled to refer to the Boulder-clay period. There is no ambiguity in this section. The chalk rises from the railway-level in bold cliffs, 60 or 70 feet high, capped here by chalk-drift, and there by fine, yellowish, stratified gravel—the latter in certain spots, e. g. the lime-kilns, coming down almost to the level of the road, and again rising up to near the top of the cliff. The beds of chalk undulate a good deal; and the older gravel follows its curves into curious depressed spaces, both north and south of the station. These depressions are, as the section will show, due not to erosion, but to faults. The upper gravel, which fills pipes in the chalk, and everywhere caps both chalk and drift, is much more varied in its composition than the lower and older gravel; often it is a chalk-rubble, especially along the higher ground, but interstratified with gravelly loam, full of broken and worn chalk-flint. More commonly it is a darker-coloured, yellow, gravelly clay or loam; and in this latter condition it may be seen in the large deserted gravel-pit just south of the bridge for the high road from Hitchin, south of the station. Close