Hello and welcome back to Fossils on Friday!
Before we conclude our exploration into red rocks, and talk about how they formed, we are going to look at a one location where they are very prominent. That place is Nesscliffe Hill in Shropshire.
Nesscliffe Hill is part of a large country park that was all once a huge quarry. The cliffs go up a vertical 30 metres, and are that beautiful deep orange-red colour. The site itself has a long and varied history, with an iron age hill fort, and highwaymen hideouts! But it’s the geology we’re looking at, and in particular some of the interesting things you can see in the cliffs themselves.
The quarried rocks can be seen all around the area in various houses and other buildings. The sandstone is very hard and tough, perfect to use as a building stone.
In the old quarry itself, you can see exactly where the building blocks were taken from, and you can get a really good look at the details of the rock.
The red sandstone at Nesscliffe has a lot of crossbedding in it, as does most other red sandstones around the world. What is cross bedding? This is where the sand has been laid down sideways, in layers on top of each other, pushing it up into piles as it gets deposited. This is an important indicator of how it was deposited, and by which means.
There is an assumption that in geology, the bottom layer got there first, then the next, then the next. But crossbedding challenges this somewhat and is a strong indicator that sediments are not deposited vertically, but horizontally, building up as they continue to get pushed up. This is what we shall be dealing with next week, as we look at how this sandstone formed all around the world.