Thursday, January 17, 2008

Coal Seams

Boys Grave and Cannop Ponds Forest Trail

Stop 6 – Coal

You are standing in front of an outcrop of shaley Pennant sandstone and thin bands of coal. Look at the diagram notice how numerous coal seams of the ’Crow Delf’ series, tilt and come to the surface (‘outcrop’) between here and Cannop Ponds.

This particular outcrop is thin and unworkable so has not earned itself a name, but it lies between two much thicker bands of coal called ‘Starkey’ and ‘Rockey’, both of which have been mined extensively.

When you move on you will see across the stream grey, clay coal waste tips which are now tree covered, evidence that ‘freeminers’ of the Forest once worked here, mining the ‘Starkey’ seam.

Other seams you will cross have romantic sounding names like ‘Breadless’, ‘No Coal’, ‘Bry’, ‘Twenty Inch’, and ‘Little’, names that almost tell a story in themselves. Can you imagine what heartbreaks ‘Breadless’ caused before it earned such a name?

All these coal seams were formed 300 million years ago by plants in shallow lakes dying and accumulating as peat; this is compressed, as sand is piled on top, and eventually fossilizes into coal. You can almost see the plants have been laid down in layers with the occasional washing over them of sand laden rivers.

Follow along by the Stream

The path goes through a mixed oak wood. The leaves decay quickly and give a rich humus to the soil which enables many small animals to live in it. You are approaching the main part of the circular valley round the Forest, where most of the important coal seams are found, and the stream crosses these every few yards. If you look carefully, you will see traces of some coal seams mentioned above in the banks.

Brambles are common. The thorns they carry are to help them clamber over the brushwood, not just to hurt people.

The stream you have been following is called the Mersiche Brook, and odd name, probably from the Anglo-Saxon meaning ‘boundary stream’.

It has many meanders here, which is typical of a stream flowing over a fairly flat floor to a valley.


This text was written by B. V. Cave of the Wilderness Wildlife Centre Mitcheldean and M.J. Dunn, Forest Warden, for the Forestry Commission 'Boy's Grave and Forest Trail'. © 1974


No comments: