Summary

The concealed valley beneath the Church Stretton valley floor is interpreted as water-cut, sloping gently down from north to south and becoming the buried floor of the Marshbrook Gorge. In this were laid down outwash gravels and tills of a valley glacier, which may be interpreted as making two advances separated by a retreat, and which terminated just north of Little Stretton. This glacier carried erratics derived from the Breiddens and Stiperstones, the Trias of Cheshire, the Lake District and the floor of the Irish Sea, an ‘Irish Sea’ assemblage. Deposits above the tills can be dated, by pollen and radiocarbon, as Zones I and II, suggesting a Late Devensian date for the Irish Sea Glacier. During Zone III and, perhaps intermittently, after that until early Zone VI, frost-shattered debris was carried down from the Longmynd valleys on the west, to form three fans across the valley, ponding up marshes from Zone VIa onwards.

The Welsh till around Marshbrook and southward is ascribed to an earlier glaciation, as yet undated, but associated with glacial gravel terraces on the valley sides and an erosion surface through which the over-deepened Church Stretton valley was cut before the Irish Sea glacier advanced into it. A series of four terraces below the glacial gravels, in the valleys of the Quinny Brook and River Onny, may eventually help to solve the question of the age of the tills of Welsh origin.

In the appendix, palynological detail is given justifying the zonal subdivisions in the organic deposits which lie above and below the fan gravels. It is also suggested that in Zones VIIa and VIIb, the influence of human agricultural activities can be recognized.

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