Geology in Bowden Housteads Wood

Flaggy sandstone exposed in a streambed

Arriving at the Sheffield Parkway after my walk through the Carbrook Ravine Nature Reserve and the south-western part of Bowden Housteads Wood, where I left the course of Car Brook, I needed to take great care when using the pedestrian crossing here.

 

Dumped supermarket trolleys

Having safely negotiated the crossing, at the entrance to the path I was astounded to encounter a couple of shopping trolleys from the nearby ASDA. As with several others that I had encountered earlier, and during a previous walk to see the Parkway Man, some mindless people had stolen them from the supermarket and dumped them there.

 

Views of Sessile Oak

On Reynolds Road, which leads to the Parkway Fire Station, my dismay turned to delight when I unexpectedly came across a large block of sculpted sandstone that is named Sessile Oak, which is decorated with acorns and oak leaves. I have not been able to discover who the artist responsible for this is, but it provided a great start to my exploration of the northern section of Bowden Housteads Wood.

 

The path into Bowden Housteads Wood

Entering the wood along the main path, I soon came across a small stream that has its origins to the south of the Sheffield Parkway and, with no thick undergrowth to hinder me, I followed it downstream to see what rock exposures I could find in its banks.

 

The geology around Bowden Housteads Wood

The geological map shows that the woods occupies an area of the Pennines Middle Coal Measures Formation, which is dominated by siltstones and mudstones but also shows a coal seam – possibly the Swallow Wood seam, which was exploited in the Shirtcliffe Valley.

 

Siltstone fragments in the streambed

In the upper reaches of the mainly dry stream, I didn’t see any exposures in its banks but the streambed is littered with small thin pieces of dark grey siltstone, above which is a thick layer of yellowish stiff clay, and this continues for some distance.

A measured section showing various types of rocks

Such clay is typically the product of weathered mudstone, as I have encountered in my back garden in Treeton, and in nearby boreholes this is logged immediately below the topsoil; however, in boreholes that penetrate coal seams, a seatearth is recorded immediately beneath the coal and this has the composition of a fireclay or a ganister, both of which have been mined extensively in the Sheffield region.

 

Siltstone fragments in the stream bed

Continuing downstream, this sequence of dark grey siltstone overlain by clay doesn’t alter perceptibly and, occasionally, a slump in the stream bank reveals the yellow colouration of the clay and broken down fragments of subsoil within it.

 

Yellow clay exposed in the stream bank

After walking for a few minutes, I finally found undisturbed beds of siltstone bedrock in the streambed, where the thinly laminated nature of this rock is clearly visible. Although in very many places it is possible to get down into the streambed, to closely study the rock or to collect samples, I just made my observations from afar on this occasion.

 

An exposure of siltstone bedrock

Shortly after the confluence with Car Brook, the course of the stream starts to steepen and cuts deeper into the underlying rock to expose the bedding planes of a flaggy sandstone, with the occasional block of more massive sandstone projecting from the banks downstream.

 

Flaggy sandstone exposed in the streambed

Having come across one of the principal paths in the woods and meeting a fellow walker, I asked for directions on the best way to make my way back towards the Handsworth Road junction on the Sheffield Parkway.

 

Exposed blocks of massive sandstone

Taking the recommended path, I then came across another small watercourse that joined the Car Brook, which had vertical sides like an excavated trench and rippled flaggy sandstone, with marked iron staining, forming the bed.

Flaggy sandstone exposed in a streambed