Saturday 27th April 2013
Natural History Walk at Black Rock and Longwood,
This month had been colder than usual when twelve of us met at Black Rock Gate to visit two of the Somerset Wildlife Trust's reserves. Our luck held again and we enjoyed a lovely sunny afternoon.
Setting off up the drove towards the quarry and the old lead mining remains at Velvet Bottom we were surprised to see the effect the recent heavy rains had had on the normally grassy walkway. The underlying rock had been exposed and broken up; in places this was down to a depth of 2 to 3 feet.
Interestingly the dark muddy limestone lumps of rock showed evidence of deposits of crinoidal material, similar to modern coral reefs. The derivation of crinoidal is from the Greek, "krinoeidis" meaning in this case lily-shaped organisms. It is believed that this limestone was laid down in the Carboniferous period about 340 million years ago when Britain was in the tropics.
Further up the drove nearer Black Rock quarry the walking surface returned to normal. We stopped at an old lime kiln which Heather described as having been checked out by the CHERT archaeology group under Vince Russet's guidance, and it was at this point too we could see that there had been very recent rock falls from the quarry face which we were careful to avoid.
At the gate leading to the large separating beds of Velvet Bottom, Heather spoke to us about how the Romans had mined lead in the valley almost two thousand years ago. These beds were utilised again by the Victorians, but the lead recovery proved uneconomic.
On reaching Longwood we followed the Nature Trail but were disappointed to see only a few English bluebells in flower. These had narrow leaves and creamy-white anthers with petals strongly rolled back. The Spanish variety has broader leaves and clear mid-blue anthers, and no rolling back of the petals. The wild garlic (Ramsons) had not flowered yet.
On following the brook back out of the wood we found what we believed to be a redirection of the water flow into a hidden sink hole that local volunteers had put in place in previous weeks to prevent further flooding down the gorge and into the town of Cheddar. This event had been shown on local television.
Possibly because of the prolonged winter, fewer flowering plants were seen. However we did see wood-anemone, greater and lesser celandine, violets, cuckoo flower, ground ivy, wild strawberry, primrose, broom-rape a (parasite), and possibly sun spurge. Not in flower were dog's mercury and unknown sedges. Birds seen were robin and wren; those heard were nuthatch, raven and green woodpecker. Please follow the link below for further information.