Manchester Building Stones
The North West Geologist
|A Building Stones Guide to Central Manchester|
Third Edition (2014)
Four self-guided walks through the city centre
Now available to purchase
Newsletter - June 2017
The full, illustrated newsletter is available as a pdf for download.
Text extracts are given below.
New Natural History Museum Fossil Explorer mobile app
The Natural History Museum in London has just released a new version of the free Fossil Explorer app, a field guide to the common fossils of Britain that helps identify fossils based on where they are found.
Whether seeking ammonites in Lyme Regis, marine reptiles in Whitby or trilobites in Girvan the beginner and more experienced collectors alike can learn about their finds and what else may be beneath their feet.
Through Fossil Explorer users have access to the combined expertise of the Natural History Museum and the British Geological Survey. It is based on information from the Museum's popular British Fossils book series; the app offers details about more than 1,200 fossil taxa as well as local geology.
Thanks to an interactive geological map, Fossil Explorer suggests likely fossil matches based on where they are found, giving a list of fossils known to occur in rocks of the same age. Introductory facts and illustrations help beginner fossil hunters get started while additional information enables more experienced fossil collectors to delve deeper.
New functionality in this release allows users to create and share lists of fossils they have found and set wish lists for future discovery.
We hope the app will encourage budding citizen scientists around the country, inspire a new generation of explorers and get people thinking differently about the natural world.
The app is available for iOS and Android. More information and download links are available on the Museum's website.
[I loaded this app onto my Android system, but sadly I could not get it to run. Looking at some of the comments it appears that other people are having the same problem. Editor]
Congleton Edge and Mow Cop
We met at the lay-by on Congleton Edge where Eileen Fraser (our leader for the day) talked us through the geology and associated history of the area before we looked at specific locations.
Congleton Edge (SJ868587)
The Romans were the first to take limestone from the area, using it to make mortar. More recently the older limekilns are near the top of the hill, but later ones are nearer the railway in the valley. Before the railway was built the canal was used for transport. Small coal seams were mined for the steel industry in Stoke-on-Trent, but volcanic intrusions and faulting made coal extraction difficult.
The well line is marked by the location of houses and farms. Some of the house names tell of their origins - Limekiln Farm, Beacon House, Millhouse Farm and Brook House.
We walked down to a quarry (SJ870589) in the Chatsworth Grit (cf Teggs Nose above Macclesfield) where the beds dip at 60°. From here we could see the Red Quarry on Bosley Cloud and the glacial sediments on its flanks, which are much unconsolidated. Bosley Cloud is at the apex of a southerly plunging, asymmetric syncline on a large scale anticline. Our next stop was at SJ873592; here too the sediments are unconsolidated. So is the outcrop by the quarry waste or glacial? It is of angular, broken-up material and is the correct height for a glacial deposit.
However, nothing was found that was not local and there is a large quarry just over the top of the hill. So we decided it must be quarry waste that had been tipped over the edge. We then walked a short way along the footpath at the top of the quarry, which is in massive sandstone and by the footpath the bedding is very steep to vertical.
Mow Cop (SJ857574 for parking)
Eileen talked us through the regional picture. Namurian delta systems were coming in from the north, but are the sediments here from the Wales Brabant system to the south? The nearby Roaches are from the south so theory is that the Lower Chatstone is from the south, but the Red Rock above is from the north.
The nose of the Mow Cop anticline is just beneath the castle/folly. The bedding is difficult to see and to interpret in the small quarry though the beds clearly dip and slickensides are present; the faulting pre-dates folding.
Very coarse grained querns were extracted from the quarry as were needle-like barytes, which could still be seen. There are more pebbles here than at nearby Bosley Cloud.
To finish we had a look at the Old Man of Mow. This is a 65ft high, unquarried stack of rock dating from about 1530. Why? One theory is that it was poor quality stone because it is on the edge of the Mow Cop fault. Another is that it was left to support machinery.
Over towards Biddulph we could see more evidence of historic coal mining.
This was a very interesting day relating the geology to its changing exploitation over time and, therefore, to the presence of settlements. The trip also added to previous MGA trips to Teggs Nose and Bosley Cloud.