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Earl Sterndale
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Excursion to Earl Sterndale - Brenda Armitage
We gathered in the shade of trees around Earl Sterndale church gate. It was going to be a HOT day. Harry lent a spare hat to one member, and began his welcome and introduction. As if on cue, the church bells rang out the call to morning service. Harry could not compete.
A short walk to the north led to Jericho Quarry. A well weathered face of Chee Tor Limestone was studied. This limestone was laid down in Dinantian times in a shallow water lagoon (shelf) environment. The search was on to find examples of the colonial fossil Lithostrotion and also Davidsonia septosa. Not easy until your eye ‘was in’, especially as the Lithostrotion had been overturned by currents, and lay in a mass of crinoid debris.
We turned to look at the landscape to the south and west. In crystal clear light the outlines of Hitter, Parkhouse and Chrome Hills stood out in sharp relief, and beyond were the level summits of the Staffordshire moorlands. Harry began a geological interpretation of this view. Almost at once a hundred or more motor bikes roared up from the valley bottom along the road through Glutton Dale. Harry had to give in again!
Within a distance of 500 metres or so, via Glutton Dale, we would cross from the shelf limestones at Jericho Farm to the reef limestones of Parkhouse and Chrome Hills, formed on the edge of the deeper waters, which surrounded the lagoonal shelf. Our path led down across a nettle-rich field. Part way down a spring is sometimes visible, marking the point where clay/shale rocks occur. The ruins of a lime kiln stand in the eastern corner of this field.
On through Glutton Dale, eroded by sub-glacial streams and melt-water. The farmer’s hostility to visitors meant that studying changes in the limestone formations from shelf to back-reef and algal limestones was reduced to a quick glimpse as we walked along the narrow, busy road. Through Glutton Grange farm yard we took the path north up a dry valley. A few scattered hawthorn trees on the valley side offered some tempting shade - time for lunch.
Earl Sterndale, notes by Keith Poole
20 intrepid geologists (plus Bobby the dog) set out on a warm day to explore the reef limestones exposed near Earl Sterndale, Derbyshire, led by Harry Briggs.
First stop was the road above Jericho Farm, for our first view across to Parkhouse and Chrome Hill, which form the edge of what was once the lagoon where the reefs were formed. This viewpoint was from what would have been the back reef, proximate to the land. Harry explained that the exposure was brought about by the effect of glacial meltwater during the last ice-age when there may have been a sheet of ice a mile thick in the area. The meltwater flushed out the mudstones and shales, depositing them on the far western wide of the reef.
Next to Jericho quarry to look for fossils in the massively bedded grey limestones, accompanied by what seemed to be hundreds of motorcyclists tackling the ascent through Glutton Dale. There weren't many fossils, but we did find a brachiopod or two, crinoid fragments and evidence of corals. The owner of the picturesque cottage next to the quarry showed us a fine brachiopod specimen he'd found in the garden.
Descending carefully through the narrow Glutton Dale (which may have been a natural channel through the reef, or may have been gouged out by the glacial meltwater), we noted the limestone here showed no bedding. Gerry pointed out the Mare's Tail (cidularia) growing alongside the road. Best place for it.
Down to Glutton Grange farm, where Bobby the dog made a new friend, and we departed from our planned itinerary to ascend an unnamed gully, noting the lushness of the vegetation on the Namurian shales compared to that on the limestone, as we stopped for lunch in whatever shade we could find under the gorse bushes. This location would have been in the lagoon formed between the back reef and fore reef.
We continued upwards to get a fine view of Dowall Dale, and a few more motorcyclists. Harry told us this forms the fault line, with a 400 foot throw, giving rise to the line of springs visible along the hillsides. Harry also pointed out that throughout Derbyshire, settlements have grown up at the sites of springs associated with volcanic ash beds. Much of Derbyshire's mineral wealth is due to volcanic activity, hot water causing the minerals to be precipitated in veins throughout the limestones. The descent down to Dowall Dale was fairly steep, bringing us to the narrow road that runs along the Dale.
With the temperature rising steadily, we made a welcome stop at Dowall Hall farm, with its tea room. The farm's location is due in part to the water which emerges from the fault, hidden by trees, but the recent dry spell meant there was no water visible above ground. Harry found a nice example of complete brachiopods in a piece of limestone exposed by a recently fallen tree. After examination and discussion, it was donated to the tea room for other walkers to admire. And to keep English Heritage off our backs.
Several slices of cake later (how many, Glynis?), we set off again down the road towards Parkhouse, with its columnar knoll reef of algal limestone looking even more impressive as we approached, leaving Chrome Hill unexplored on our left. Chrome Hill apparently derives its name from the crescent shape of it's ridge, similar in appearance to a 'chrome', the local name for a sickle used to cut grass. The edge along Chrome Hill is cetainly precipitous. This location would have been on the fore reef, with the open sea on the western side from which we approached. We skirted the edge of Parkhouse, noting the unconformable contact between the Namurian shales and the reef limestone. Some goniatites have been found here, but we didn't see any.
There was some debate as to the reason for the ridges on the hillsides; Glynis identified them as solifluxion terracettes, but Gerry thought they might be the result of differential congelifraction. I'm in two minds about it. They looked like the result of repeated freeze/thaw events to me.
Heading back uphill towards the road, the party split into two groups; those who favoured the return walk back up through Glutton Dale along the road, and those who opted for the cross-country route over Hitter Hill. We hill-climbers won, and got back to the pub first, for a refreshing glass of lemonade accompanied by a three piece band in the pub garden.
A cracking day out, in which we traversed the back reef, lagoon and fore reef, noting the different environments that would have prevailed at the time. My compliments to the leader. |
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