5th January 2017:
Parked at Ellick Farm and followed the path keeping close to the boundary wall, then turning to head up to the trig on the top of Mendip – Beacon Batch at 325-metres. Passed a group of grazing ponies on the way.
I enjoy the sight of the ponies, and the cattle too, perhaps reminiscent of ancient herds in the past, a sentimental thought, of course.
Along the route from Beacon Batch to Rowberrow Warren the path follows the Blackdown pericline, the underlying geology comprises Devonian Old Red Sandstone (Portishead Formation).
As the path enters the warren and dropping down to the valley the geology is Triassic Dolomitic Conglomerate. In Rowberrow Forest I came across several examples of ‘angel’s hair’ an ice formation where water is extruded from fallen branches as it freezes.
Down the valley for a short distance before crossing the stile into the AWT reserve and a steep climb up to the hillfort at Dolebury Warren. Here leaving the Dolomitic Conglomerate and crossing the boundary between the Lower Limestone Shale and Black Rock Limestone of Lower Carboniferous age.
Across the warren and back onto Blackdown passing Reads Cavern, Rods Pot, and Bath Swallet along the way. As I approached West Twin Brook there are good views of the exposed limestone cliffs in Burrington Combe.
In West Twin Brook there are good exposures of the Lower Limestone Shale near West Twin Brook Adit.
Further down the stream is Sidcot Swallet, a cave in Black Rock Limestone.
There are interesting rocks in the stream bed too, such as this fossiliferous limestone.
From the bottom of West Twin Brook I followed the road passing Aveline’s Hole and the Rock of Ages before crossing the highway to gain the steeply ascending path behind the toilet block, stopping to look at the thin exposure of Dolomite in the car park.
At the top of the path is found Burrington Camp, a probable Iron Age univallate hillfort or religious enclosure. It is sub-rectangular, defined by a ditch and bank and appears to have been constructed in two phases.
Then followed the path over the common to return to the van at Ellick Farm.
