Geology in Dronfield

 

A rock face on Chesterfield Road

When planning my day out to Coal Aston and Dronfield, I referred to the Sheffield Area Geology Trust (SAGT) website, where a lengthy description of the Silkstone Rock mentions various rock exposures on the east side of Chesterfield Road and Sheffield Road, some of which I had found using Google Map Street View. 

 

Exposures of the Silkstone Rock on Green Lane and Mill Lane

 

Having unexpectedly encountered an old quarry and a very small outcrop on Green Lane and a few other quarry faces on Mill Lane, which I have since discovered are included in one of the Dronfield Geological Walkabouts that were produced by Mike Romano for the Dronfield Heritage Trust, I looked forward to trying to find those identified by SAGT. 

 

A rock face on Chesterfield Road

 

After photographing Lea Road Bridge from the footbridge at Dronfield railway station, I continued north along the east side of Chesterfield Road and was very surprised when passing various converted shops and a new apartment block and a roadside cottage to see a small section of a rock face that was currently being cleared of vegetation. 

 

Cross-bedding in the Silkstone Rock

 

I didn't ask if I could take a closer look and take a sample, but my photos show that the Silkstone Rock is strongly cross-bedded here. I have wondered if this and other rock faces marked along the east side of the valley might relate to road widening rather than commercial quarrying, especially since there is another rock exposure to the rear of a yard behind No. 1 Sheffield Road. 

 

No. 1 Sheffield Road

 

The 1854 edition of the 6” Ordnance Survey (OS) map shows a small quarry on Snape Hill Lane, which is not shown on the 1898 1:25,000 scale map, but both maps show another larger quarry further north along Sheffield Road - near a place named Alma. 

 

A quarry marked on the 1898 Ordnance Survey map

Firstly asking permission from the receptionist at Banner Jones Solicitors to have a quick look at this small outcrop that I could see from the footpath, I proceeded to discreetly obtain a couple of small samples of sandstone with my Estwing hammer. 

 

An outcrop to the rear of No. 1 Sheffield Road

The specimens are fine grained and strongly iron stained, with weathered out small elongated clay ironstone pellets and the development of dense thin bands of ironstone. The Pennine Lower Coal Measures Formation strata associated with the Silkstone Rock typically have a very high iron content, which often develops into seams that were extensively mined wherever they occurred in Derbyshire and South Yorkshire. 

 

Specimens of Silkstone Rock

 

50 m further along Sheffield Road, I was very interested in a grand looking set of steps, with iron bollards to the entrance, which I later learned connects to Snape Hill Lane. What most caught my eye was the pile of thick sandstone slabs that have been laid out next to the boundary wall of  a now demolished Wesleyan Methodist Chapel, which is shown on the 1898 OS map.

A set of steps leading to Snape Hill Road

My curiously got the better of me and I ventured for a few metres up the steps, which is marked on the current OS map as a public footpath, to see an open green space that, at its north-eastern extremity, my photo shows as having another rock face exposed behind the trees and shrubs. 

 

A green space with a rock face obscured by trees

 

Continuing to Snape Hill Lane, I looked for the rock exposure mentioned by SAGT – photographed in 2012 - but I couldn’t see any rock exposures and suspect that this might lie beneath the very thick vegetation that has encroached its irregular north bank at the junction with Sheffield Road. 

 

An overgrown quarry face next to the former Nawabs Brasserie

 

From this point onwards, Sheffield Road no longer retains its Victorian character and is partly lined with some quite large C20/C21 retail buildings and I quickly carried on to the exposure that SAGT said was next to an Indian restaurant. It is quite overgrown and, being conscious that I still had several listed buildings to visit for my Photo Challenge, I just took a couple of photos before returning to Lea Road. 

 

A detail of the quarry face