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Haversham Mill River

Grid reference: SP 839 435

Location: Haversham-cum-Little Linford, via the Swan's Way at Mill Farm

This is a pretty site which offers a glimpse of the Jurassic (Liassic) rocks as well as river processes with a meander and river terraces all highly visible. This is the only current exposure (in this area) of the oldest rocks in Buckinghamshire - the Upper Lias mudstones and limestones. However, there is some exposure further north in the county (in the Olney area and this rock can be seen in the local buildings there and is used in many gravestones throughout the County).

Although the section is degraded the layers of muds, marls and thin limestone bands can just be seen in the banks of the meander. These are mid- to pale-grey clays and pale-grey limestones. Fossils are present in the form of broken shells (various bivalves as well as some trace fossils including burrows. Ammonites have been found in these rocks in the past). Access to the rocks is not easy, unless water levels are very low. Therefore, it is not recommended that visitors attempt to sample the rock layers due to the potential of falling in the river.

The following points of interest can be considered on a visit:

How rivers ‘work’ (eroding rocks in some places, depositing sediments in others).

Geomorphology of the river and its floodplain (use an OS map).

Meandering rivers - what are they and where do they occur? Low gradients and wide floodplains are typical of meandering rivers.

The floodplains and river terraces (1st) - processes at work. The oldest river terraces (ice age) are highest in the landscape; terraces get younger as they approach the lowest (modern) river level

Biological studies - the different environments in and around the river, and re-colonisation following the quarrying activities (south of river)

Slope instability is very noticeable within the1st Terrace and above. In addition, soil creep, slumping and rotational slip are all visible at this site.