Leader: Helena Crouch
Ten members joined the leader for the walk through Vallis Vale, a biological and geological SSSI, containing ancient woodland and the famous De La Beche Unconformity. After weeks of wet weather, the paths were very muddy but passable, and the Egford Brook and Mells River were now within their banks.
The path from the car park at the southern end of the site, led past a field and into the woods. Lesser celandine and wood anemones were blooming, a buzzard flew overhead and chaffinch and wren were heard. The path followed the Egford Brook, until its confluence with the Mells River. We followed the Mells River through the woodland, until we reached a large clearing, the floor of an old quarry. Song thrush, great tit, nuthatch, and greater spotted woodpecker were heard.
The remains of an old railway line or tramway poked through the ground, a reminder of the industrial past of the area: quarrying of the limestone (for lime and for road-stone) and iron working. Further along the path we would see the remains of lime kilns. At the far side of the clearing the cliff of the quarry face rose up, clearly showing the unconformity between the yellow-coloured, horizontally bedded Jurassic Inferior Oolite limestone and the underlying grey, massively bedded and steeply dipping Carboniferous Vallis Limestone.
Herb robert, ivy-leaved speedwell, and barren strawberry were in bloom near the base of the cliff and also more lesser celandines. A clump of primroses could be seen near the top of the quarry face. Helena identified the hawkweed, Hieracium speluncarum, growing on the lower rock-face, an alien, which grows in Mells and is spreading.
The path continued along the Mells river. A flock of winter thrushes flew over, possibly redwings. The trees near the river were covered in an amazing abundance of moss, not just at ground level, but also along the higher branches. On the ground fox-tail feather moss (Thamnobryum alopecurum) was growing, like miniature trees. Opposite-leaved golden saxifrage was just coming into bloom, as well as male dog’s mercury and moschatel.
A heavy shower caused us to take cover underneath a railway arch – there is a rail line still in use, to Whatley quarry. With the aid of a magnifying glass, Terry Doman showed us the tardigrades feeding on the algae on the brick wall of the arch.
The shower over, we continued along the path by the river. Scarlet elf cup (Sarcoscypha austriaca) was spotted amongst the leaf litter. Clumps of snowdrops were going over. Ferns were flourishing in the damp atmosphere: hard shield fern, with its glossy leaves, and a short distance away, soft shield fern, with which it can hybridise, maidenhair spleenwort, intermediate polypody, and large numbers of hart’s-tongue ferns. Leaf miners were evident in some of the hart’s-tongue leaves. Terry explained that these were the larvae of micro moths, Psycoides verhuella and/or P filicivora.
We turned round when we reached the road bridge over the Mells River at Great Elm, and returned largely along the same path, but along the opposite bank of the river for one stretch. Here we found white violets (sweet violets) and the uncommon alternate-leaved golden saxifrage, spurge laurel and the garden laurel (Prunus laurocerasus) an invasive species. Some fieldfares flew over and a goldcrest could be heard singing (by those with good hearing). As we returned to the car park a raven called.