The River Severn did not originally flow south. It was originally the River Dee, and at the start of the last glacial period the river flowed north. However, as the glacial period progresed the Irish Sea iced up, and the Dee's way became blocked with a tremendous amount of ice. With the river's flow blocked it started to form a lake (known as Lake Lapworth - the modern site of Newport, Shropshire, was on the northern edge of this lake).
Eventually, at some point in the middle of the last period of glaciation over 10,000 years ago, the water level being dammed by the Dee's blockage rose to be higher than the lowest pass in the hills to the south and the river spilled over, carving its way through and creating the Severn Gorge, and the River Severn.
This gorge exposed minerals and an abundant supply of water - providing both power and transport. Fast forwards about 10,000 years and you are now standing in that gorge, which became the cradle of the Industrial Revolution, which changed the face of the Earth!
I encourage you to visit the local museums to understand how important this area was between (roughly) 1700 and 1914. Especially around the building of the world's first iron bridge, which is in front of you as you stand at GZ.
Abraham Darby III paid for this bridge to be built to improve access across the gorge - replacing a ferry. He made no money at all from the operation, in fact ended up a lot poorer that he started, but can you work out the benefit that this bridge brought, in terms of the physical dimensions of the gorge, that resulted in the world's first iron bridge to be built?
eMail your answers to these questions to EARTH@sharant.com
Question 1: What is the difference in height between the river (where the ferry would have docked, approx) and the street (eg outside the Tontine Hotel)? (use the 'elevation' capability in your GPS unit, if you have one, or local info boards). Note down the actual altitude of the bottom of the gorge, for use in Q3…
Question 2: What is the width of the gorge where the bridge spans, approx? (again, use the local info boards or your own GPS unit to measure the distance).
Now let's compare this with the power of the water itself in carving the landscape over 10,000 years ago! Travel to the viewpoint at Waypoint 1 (N52 37.668 W002 29.867), which represents (very approx!) the low point of the hills before Lake Lapworth tipped over all those millenia ago. The gorge you see below you was carved by the River Severn alone!
Question 3: What is the DIFFERENCE in height between the bottom of the gorge and your position at Waypoint 1 now?
Question 4: Some research needed here (why not visit a local museum to find out?). Name three of the important minerals that the carving of the gorge has revealed, which were so important in the industrial revolution. There's quite a lot of them, so bonus points if you get more than three!
Photo Requirement (optional): To prove you are really here geocaching and not just submitting old holiday photos, please feel free to take a photo of you with your GPS unit, with the gorge and/or bridge in the background. Perhaps ask a passing tourist for help with this? Note that this is an optional task, not a requirement!
Click here to also find ten LAB caches that will visit the historical places in the beautiful Severn Gorge!