Introduction
At the cache location you will find a stone memorial to The Peterloo Massacre which took place close to this spot on 16 August 1819 after some 60,000 to 80,000 people, some of whom had walked from as far afield as Wigan, Rochdale, Saddleworth and Altrincham, gathered to demand reform in parliamentary representation.
Shortly after the meeting began and whilst the orator Henry Hunt was making his address, local government forces charged into the crowd on horseback and with swords drawn, injuring 700 and killing 18 men, women and children.
People have long campaigned for a fitting, permanent tribute to the events of that day and the fruit of their efforts is a fine memorial constructed in granites, slates and sandstones which provides a lasting reminder of the sacrifice made by the fallen in the name of democracy and a record of the places they came from, unveiled in time to mark the 200th anniversary of the massacre.
This EarthCache looks at the types of rock used in the memorial's construction - focussing on the steps.
Logging Tasks
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As explained in the Background information, the risers of some of the steps are engraved with the names of people or places.
Some of these engravings are listed below. Locate each of the listed engravings and tell me, in each case, which type of stone they are in, using the specific names given on the cache page.
- Gorton
- Joseph Whitworth
- Chadkirk
- Flixton
Also:
- Locate the Cwt-Y-Bugail Slate and describe the feature it is used in. Extra marks if you can tell me what this feature symbolises 😉
- Please provide a photograph of yourself or an identifiable personal possession at the memorial as proof of your visit. Feel free to include photographs with your log that do not show the specific features from the logging tasks - no spoilers please. In the interests of allowing everyone to experience the EarthCache fully for themselves obvious spoiler photographs will be deleted.
Background
The monument is comprised two elements - a circular tower of eleven concentric steps and a smaller circular section which is adjacent to the tower and flush with the pavement surface. This smaller section is a replica of the features present on the upper surface of the eleventh step, which point to and date similar campaigns in other countries, and is a modification to the original design for the benefit of those who cannot climb the steps.
At the base of the tower a shallow ramp of Portland Stone follows part of the circumference of the bottom step. Close examination of the ramp reveals fossilised shells of sea creatures.
This EarthCache focuses on the tower of eleven concentric steps and the rocks they are made from.
In common with all staircases, each step is comprised a tread - the horizontal surface of the step and a riser - the vertical edge of the step.
Some of the treads are inlaid with motifs representing the protest and its aim of fair, democratic voting rights for all.
Some of the risers bear the names of those who died. Other risers bear the names of surrounding towns that people travelled from in order to take part in the protest and these are arranged so that they face the compass directions of those places, and also arranged by step circumference as an indication of the relative distances that people travelled from those places in order to be heard.
The Rocks Used In The Monument (in alphabetical order)
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Broughton Moor / Westmorland Green Slate - a sedimentary rock laid down in deep seas around 426 to 427 million years ago during the Silurian Period and quarried today, as its name suggests, on Broughton Moor in Cumbria.
The rock is described as hemipelagic, which refers to rocks which include lots of silt and clay-sized particles but its easy to see that there are also larger sediments in the makeup of this slate, resulting in a coarser texture.
The soft green tint arises from the presence of the mineral Chlorite. Most slate starts life as silt and mud but the sediments in this slate include volcanic ash or tuff.
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Cop Crag Sandstone - another sedimentary rock which I've not seen before and which I absolutely love for its dramatic appearance 😍.
This sedimentary bedrock is quarried in Otterburn in Northumberland and was laid down approximately 319 to 329 million years ago (mya) during the Carboniferous Period.
Cop Crag Sandstone is described as a yellow / pink fine-grained sandstone but I’d say it’s more burnt orange with sometimes deep pink, almost red, patches and banding. On the day of my visit it looked fantastic but there had been some rain that day so the colouration may have been darkened by the rock having been wet.
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Corrennie Pink Granite - Granite is an igneous rock which makes up the bulk of Earth's continental crust. In fact, research indicates that Earth is quite special in this regard as it's the only planet in our solar system where granite is found!
This particular granite is quarried near Aberdeen but nailing down its age was a bit of a challenge as the quarry seems to include more than one magma. Conclusion is though that this granite is somewhere between 444 and 485 million years old.
As you might expect from its name, this granite has a pink hue and also has a slightly uneven surface texture arising from the way its crystals interlock.
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Cove Sandstone - is classified as a New Red Sandstone of Triassic age. It is a fine-grained stone, red/brown in colour with varying bed definitions (types of layering).
It formed formed approximately 247 to 252 million years ago in a local environment previously dominated by rivers.
In this monument the Cove Sandstone looks similar to the St Bees sandstone with the only obvious difference being that the Cove is a paler shade of rust-red. In fact, if you found a piece of weathered Cove among beach shingle you'd be forgiven for wondering if it was a bit of brick 😄
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Cwt-Y-Bugail Slate - a metamorphic rock formed from silt and mud deposited on the sea floor in the Ordovician period, approximately 450 million years ago, which metamorphosed into slates as a result of pressure arising from the colliding of tectonic plates during the Caledonian Orogeny.
At first sight I did think this was a slate but I'd never seen one so dark - it's almost black! It turns out that this colouration is due to the original muds being deposited in a low oxygen (anoxic) marine environment.
Most of the rocks described here have been used to form entire steps, and also as inlay material used for decorative and symbolic motifs, but this particular slate hasn't been used to make a step. It is, though, distinctive and easy to spot.
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De Lank White Granite - I'm by no means an expert when it comes to identifying rocks in the field, which is why I'm such a fan of urban rocks which are polished and make identification easier, but this one had a look of Cornish granite to me with its abundant and prominent white feldspar crystals, many of them rectangular, and something of a beige tinge to it, paler than I've seen before but still noticable.
Sure enough, it turns out that the quarry is on Bodmin Moor 😊.
This particular granite was formed around 272 to 331 million years ago during the Permian and Carboniferous Periods.
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Dolerite - I'll be honest - I had no idea what this coarse, grey rock was
Under magnification I could see that it was crystalline and therefore came to the conclusion it was igneous - and had a hunch it might be Basalt, but that was as far as it went 
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But then - joy of joys - one of the stone masons who engineered and installed the monument appeared at GZ with his lovely wife and was gracious enough to share with me the pedigree of all the rocks - which made my day 😃.
It turns out that Dolerite is the medium grained, intrusive equivalent of Basalt - so my guess wasn't that far out 
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Fletcher Bank Grit - online resources describe this sandstone as buff to grey and perhaps that's how it looks in the wild but here it looks more yellow, maybe even golden! 😍.
Although it could be the numerous orange bands and swirls of iron minerals exposed on its freshly hewn surfaces which contribute that warm, even luxuriant hue.
A coarse-grained sedimentary rock laid down around 320 to 322 million years ago during the Carboniferous period and hewn more recently from a quarry near Ramsbotton or Rammy as it is more colloquially known.
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Peak Moor Sandstone - there must have been an awful lot of sandstone laid down during the Carboniferous Period - because this is another one!
This one, documented as being around 320 to 322 million years old, is quarried on Stanton Moor near Matlock in Derbyshire, situated inside the Peak District National Park
Peak Moor is a fine to medium grained sandstone, predominantly buff in colour with occasional pink markings and / or brown iron intrusions. It is essentially a free stone i.e. free of prominent bedding planes, and therefore almost equally durable in most common masonry applications, whichever way it’s natural bed is laid.
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St Bees Sandstone - another New Red Sandstone of Triassic age, described as Red-brown, very fine- to medium-grained, commonly micaceous, generally cross bedded.
In the memorial, this sandstone is a much deeper red than the Cove Sandstone, suggesting a much greater concentration of iron-rich minerals which are an indicator of hot, arid conditions leading to greater mineral oxidation (or rusting, if you prefer) characteristic of hot desert environments.
In its natural setting the St Bees Sandstone forms the sea cliffs of St Bees Head near Whitehaven in Cumbria.
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Whitworth Blue Sandstone - also known as Whitworth York Stone is a well compacted, very hard, fine grained, blue-grey cross-bedded sandstone of Carboniferous age, formed around 319 to 320 million years ago.
In the stone used in the memorial, ripples in the riser of the step can be seen more clearly than those in the tread, the upper surface, where they are less obvious due to the polishing the stone has undergone in order to produce a flat, even surface.
A member of the Millstone Grit series, this extremely durable sandstone was quarried in Whitworth near Rochdale, Lancashire.
If you've carefully read and digested the information from this cache page your tasks at the cache location should prove relatively straight forward, although you may wish to take a printed copy of the page with you so that you can check your answers while there 
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Please submit your logging task responses before posting your log.