Drawing

A View of North Cliff Quarry

On Day 2 of the XP School “Rock On!” project - having decided that we would visit North Cliff Quarry instead of Barnburgh Crags - the first task of our group was to choose the best approach.

The easiest way is to park and then walk along the path next to the school playing fields; however, Marc decided that it would be good exercise to take the students on a much longer route that was previously unknown to me.

Arriving at the edge of the quarry face, and seeing only long wild grass, I made my way around and down to a place where Marc then directed the students down a much steeper path.

Looking up to a height of several metres, I walked halfway up to demonstrate that it was safe and, taking great care, they proceeded down the path one by one and then found a place to sit down and listen to further instructions. 

Making our way to the base of the Permian reef, walking on a large rocking stone, we found a place where we could all get comfortable and I then explained the various geological features at this site – before they started drawing. One boy wanted to know why he couldn’t just take a photo with his mobile phone and one or two weren't too keen but, in general, everyone was very enthusiastic with this task.

A plant spray

The uneven and sloping ground didn’t provide enough space for the students to undertake the measuring tasks themselves, so this was undertaken by Marc and me. Standing at the bottom of the outcrop, I spoke too loudly with my measurement and, quite remarkably, my very accurate figure of 5.7 metres appeared on many drawings that I saw – despite instructions that they should be estimated with a ranging rod.

When they had finished their annotated drawings, we explored the rock face, looking at variations in the lithology and beds that are packed full of tiny fossil shells. Here, I used a water spray to highlight the details of the rock, when looking at it with the naked eye or hand lens, but some students seemed more interested in the crickets and spiders' webs.

A geological map of Conisbrough

After finishing the tasks in the quarry, we stopped briefly to look at the surrounding topography and the limestone escarpment that stretches to the north.  With the aid of a 1:50,000 geological map, which none of the group had seen before, I pointed out our position in Conisbrough and briefly explained that, here, the Rivers Dearne and Don converge - before cutting through the limestone escarpment to form the Don Gorge.

The Permian reef at North Cliff Quarry

Health & Safety

Steeply sloping ground, precipices and rock fall hazards

Geologists often work in very isolated and hazardous places, where there are precipices and dangers of falling rocks, steep and often unstable or slippery slopes, boggy ground and water hazards – amongst others.

Water Hazards, Bogs and Quicksand

As an undergraduate, whilst mapping the Borrowdale Volcanics near Keswick, I became very aware of this when, walking on the moors, I stepped into a deep boggy hole that came up to my thigh. Having spent a few weeks safely traversing the rugged terrain, it took me completely by surprise and I could easily have broken my leg. 

By myself, and in the days before mobile phones, only the sheep and their Welsh Border Collies could have possibly been within hearing range.

No doubt, the codes of practice for undertaking fieldwork have changed considerably since this time; however, other minor accidents - experienced or witnessed whilst working on scaffolds in the construction industry and cutting stone in a quarry - have reinforced my own common sense attitude towards Health & Safety.

Quarrying, stonemasonry and landfill

Both Martin Said and Marc Voltaire had undertaken preliminary visits and produced risk assessments of potential sites for the XP School “Rock On!” project and I thought that the places that we had visited on Day 1 were low risk, as far as safe access to these was concerned.

Knowing potential field trip hazards well, the students were being thrown in at the deep end to a certain extent but, when everyone decided to go to North Cliff Quarry on Day 2, we agreed that it is very important to be aware of personal and collective Health and Safety issues at an early age.

A Permian Bryozoan Reef at Hooton Pagnell

A Permian Bryozoan Reef

A Permian Bryozoan Reef

Whilst surveying a wide variety of natural landforms and active and redundant quarries in South Yorkshire, I have seen many ancient bryozoan reefs and, the Yellow Sands Formation excepted, I think that these are the most interesting rocks that can be found in this region.

A detail of the Permian reef at North Cliff Quarry

At North Cliff Quarry, one of these reefs overlies massive beds of buff coloured, cross bedded, oolitic dolomitic limestone that is full of of small bivalve fossils - often preserved as moulds - giving the rock a porous texture that distinguishes it from the beds that lie above and below them. 

The lower section of the reef mass is partially brecciated - often with a distinct reddening of the fine grained matrix, which provides evidence of the influx of muddy sediments similar to those found in the Permian marls.

From paths running along the top of the various quarry faces, there are also excellent views of the scarp and dip topography of the Coal Measures strata to the west, the limestone escarpment to the north and the Don Gorge to the east.

Like so many old quarries, North Cliff Quarry has attracted dirt bike riders and has been a dumping ground for cars. When I last visited the site, in 2007, bottles and cans and miscellaneous rubbish littered the place; however there was still easy access to most of the rock exposures.

 

A few views at North Cliff Quarry