Frog's Mouth
This Earthcache takes you to Frogs Mouth Quarry. A Runcorn landmark. The coordinates take you to the bottom of the highest point of the quarry. Its a very poignant place for reasons you will see when you get here. I would like to acknowledge that I took a lot of the history of Frogs Mouth from the Runcorn Historical Society website. While you are here its worth knowing that Frogs Mouth was once three times the height that it is today.
Runcorn Sandstone
The bedrock in the Runcorn area is sandstone. Runcorn is perched at the end of an outcrop of this stone which looks out over the River Mersey. From the nature of the remains of Halton Castle and Norton Priory, this stone has been used since Norman times. During the 18th century. the quarrying of the stone became a major industry of the area and large quarries were opened around the then small town. The high point of this industry may have been in the late 1800s. Around 1850 A.D. some of the earlier quarries had been worked out, and new ones had been opened south of the older quarries towards the village of Weston.These latter continues in use until the outbreak of WWII in 1939, although by then they had become shadows of the industry of 50 years earlier.
The Runcorn Historical society have made a list of all the buildings constructed from Runcorn Sandstone. The most famous of these is Liverpool's Anglican Cathedral.
The spoil from the later quarries was dumped in the older earlier quarries and today these form the basis of the Runcorn Hill recreational area which was first laid down in the 1920s. Many of the present day paths follow the lines of the old tramways which were used to carry the spoil down from the Weston quarries to these older ones. After 1939 the Weston quarries received the waste products from the nearby chemical works, and this dumping continued until the mid 1970s. They were then finally topped out with soil and today they are used to graze horses on. In the 1990s chemical vapours were discovered rising from buried chemicals which led to the abandoning of many houses local to the quarry sites, which had been built on waste rubble from the earlier quarrying. Where the solid sandstone had not been quarried proved impervious to this vapour and it had not reached the village of Weston itself.
How it's Formed
Sedimentary rocks are those which have been formed through massive compression in deep seas or deep beneath the land. Sedimentary rocks occur in layers and are formed year on year by new accumulations of soil, particles, mud and sand. These layers are compressed over millions of years and form the rocks which are visible today. Sandstone, Limestone and Shale are examples of these types of rock.
Sandstone is very coarse and grainy, normally being orange or pale brown in colour. Shale is more flaky however not as grainy as it is made up of more mud than sand compared to sandstone. Limestone is normally grey coloured due to the bones of marine species which it is composed of. Limestone is normally also very smooth to touch.
The rock at this particular location would have been formed in mud and sand deposits in a now exposed and eroded landscape. The formations here would have been miles underground however through the process of tectonic activity and movement within the earth's crust, these deposits have now become exposed to the atmosphere and the surrounding rock has been weathered away; thus leaving the rocks visible and their formations.
The history of the earth goes back billions of years and geologists use a geological timescale to date the rocks they find and base their theories upon. These rocks will have been formed in the Carboniferous era.
Logging Tasks
In order to log this earthcache you will need to perform the following tasks. Please send me the answers in an email. There's no need to wait for a reply just log away!
1) Through observations made of the surrounding rock, which other of the three sedimentary rocks (other than sandstone) mentioned are present at GZ?
2) Describe how the rocks have been layered.
3) Estimate the size of the cliff (if you like you can take the path to the top and take altitude readings from top and bottom)
4) I always find it very interesting to read the graffiti at the base of the quarry. I beleive that some of this grafiti was made by the quarry men who worked here. Visit the waypoint 53 19.872 -2 44.593 and tell me what year J Woods carved his name into the quarry. This is one of the best examples of old graffitti. If in the height of summer its hard to get to try 53 19.911 -2 44.564 and tell me what year A.Jones carved his name. You don't need to do both.
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