/ Mythical Gritstone discovered in the Mendips
major report to follow
I'm thinking of employing a secretary to deal with the flood of email requests for directions to the crag.
Im waiting for publication of the university of Bristol geology departments report before i Accept this as mendip grit ;-)
They put "real news"
I Thought they were Grammatically correcting your "Proper news"
I corrected that in the south West the term actually is Proper not real.
They Changed their Comment to Proper as they werent being a grammar Nazi, so i deleted my correction of their correction.
They subsequently Posted fixed after i had deleted.
all Clear? Good :-)
I can feel an offensive post brewing up, i had better take my medication.
I was under the impression you'd not been taking your medication for quite some time now.
looks suspiciously like limestone to me.
reminds me of the time my brother tried to convince me that seagulls were "white" crows
Nope, it is 100% gritstone.
We did lots of research!
Calcareous Grit? Looks top wizard of the first class in any case. Get it smashed in!
Is it quarried grit or just a natural buttress?! either way, top find!!!
Go on then, let's have a guess.
Part of the Beacon Hill pericline so....
Moon's Hill Quarry?
No that's Basalt.
Yep its quarried grit.
Hmm. Meant to be caving this weekend but I'll probably end up in "bloody Swildons" again!
So might just raid the club library for some light geology reading :)
Or just ask Les Williams. Bet he'll know where to find grit on the hills.....
Seeing as its not in the Peak would it be acceptable to smash a load ofbolts into it? ;-)
Sorry, couldn't resist. I wander if anyone will hit the 'report abuse' button when they see my post!
I should, because its the peaks, not the peak, and you Knows it.
You Zumerzet boys are nuts with your love of Mendipian and Wurzels esoterica.
But well done on finding some routes. Downhill Racist looks great.
Shame that one has to contact Deepstar for directions though. Have you put lip salve on the projects as well to stop the marauding Devonians from nicking them? It's just the '80s!
Dont tell ee wer tis deepstar. He be a janner :-)
We are working on the Mendip Esoteric Trail Challenge.
Nobody will ever be able to complete it.
Or want to.
Why is it a shame? I wont bite your head off.The reason for the reticence is having lost access to a small crag by puting it's whereabouts on UKC I dont want to lose another one.
Boring honeypot tosspot paedophiles
I was merely making fun of your title when the access requires anyone wanting to climb there to email some bloke for permission/directions to the rock.
If the routes aren't public why draw attention to them on a public forum?
Perhaps I've missed the point, or something.
eh? youve lost me. I didnt post anything to you.
I climbed at the Mendips once
I'll off up to the Peak this weekend so I will be keeping a close eye out for missing bits of crag and tell tale drag marks to a discreetly parked lorry ;-)
Over the last 10 years, every time i visit the Peak i always take back to Bristol a little bit of grit.............
just enough to put in my rucksack.
Those years have finally paid off
Yes, i feel so.
Janner, Chief, Gull and now most definitely a Chief.
But what have I climbed on Mendipian Grit? I may have to explore this wierdness one day.
I reckon both Buoux and Céüse could be gritstone...
I presume it is actually this (which used to be called Millstone Grit, and is a gritstone i.e. a hard sandstone of angular grains)
I did stuff on the 'Millstone Grit' (actually Marros group) in my Geology A level a very long time ago back in South Wales. Has anyone climbed any of the South Wales gritstone, and how does it compare with the Peak stuff (equally how does the Mendip grit compare)?
Interesting stuff! :)
Just the one route?
Does it outcrop in the Mendips? Still looks like limestone to me!
How on earth can you tell what it is from a picture? weird!
It's very very old quarry in the Mendips and it is 100% definitely Gritstone - unless all the local history/geological reference books are incorrect (the quarry was for Quartzite and Gritstone).
The slab that Deepstar cleaned has 4 routes on it. There doesn't really look like there is any other potential unfortunately.
As far I my rapid Googling reveals, in Wales (including SE wales) the rock-formerly-known-as-Millstone-Grit overlies the Carboniferous limestone - which is the same limestone that makes up Pembroke, the limestone of South Wales, Avon and Cheddar, so I don't see why there can't be an outcrop in the Mendips? But I am no geologist :P
Just out of curiosity, do you know exactly which rock group it is? The Marros group is supposed to be composed of the Twrch Sandstone (formerly Basal Grit), and above that the Bishopton Mudstone and the Telpyn Point Sandstone formations (together formerly the Shale Group).
PS in my search for other Marros group series climbs, I found this, which should presumably be Telpyn Point Sandstone:
...or coastal grit? :P
There's some boulders in a field belonging to my relatives, who live near Tintern. I'm pretty sure they are gritstone. Any grit outcrops in SE Wales?
I struggle to see much of a difference between the SE Wales Sandstone crags (The Gap, Tirpentwys, Cwamam, Navigation Quarry) and also the Bristol Sandstone (Winterbourne) and Gritstone.
Geologists, feel free to prove me wrong.
These boulders are grey - no hint of brown/red/orange - and the rock is iron-hard and not remotely sandy. There are also numerous embedded pebbles. The surface texture is very rough.
Three Pebble Slablet,what grade is it?
Chinny reckon ;)
Probably only Gabbro, nothing to get excited about.
No, honestly :)
Winterbourne sandstone isn't really anything like grit. Smaller particles less pebbles much softer and sandier. I guess the main simililarity is the fact they are both sandstone.
Fair dues, just checking like ;)
I guess you realise its probably not millstone grit.
More likely pennent sandstone IMO.
Yes, Yes, Yes, i am very aware of the Penant in the area (ive been developing most of it) but this is definitely grit. Do some research into the Mendips - its a thin band of grit right next to Quartzite and Coal bands.
Read the paragraph starting with "From the wooded glade....."
OK I've had another look and i see the references to gritstone in the area which aren't show on the map I linked.
A lot of the rock in south wales used to be classified as gritstone however its now classified as the Marros Group. I suspect your outcrop will be similar.
Quite possibly, but Marros is still a kind of Gritstone, and it was quarried for Millstones!
I need to take a sample to Bristol Uni.
why isnt it shown on a map where it is,people can see for them selves.it looks a bag shite anyway
Nope marros is not a type of gritstone.
The actual state of play in the geological classification of the rocks in the area seems some what in flux
However if you read the text its pretty clear these rocks do possibly differ a bit from the Marros group but appear to be atleast as different to grit as the Marros group are.
Yes but 'Gritstone' is just course sandstone.
Yep, certainly not a crag for honeypotters!
Bit more info on how the two rocks (Marros Group formally know as south wales gritstone and Carboniferous Millstone Grit) were formed.
“The Millstone Grit dates from the Namurian stage of the Carboniferous period. At this time a series of isolated uplands existed across the British Isles region. One particular east-west aligned landmass stretched from Wales through the English Midlands and East Anglia to the continent and is now known as the Wales-Brabant High though was formerly referred to as St George’s Land. Other uplands, the erosion of which would provide the source material for the Millstone Grit, lay to the north and northeast of the region. The Pennine basin received input of sand and mud largely from southerly directed rivers from these northern landmasses.Rivers running north off the Wales-Brabant High deposited material in the southern parts of the Pennine basin from northeast Wales to the Peak District. Southerly flowing rivers from this same landmass were responsible for the Millstone Grit/Marros Group succession in South Wales.During much of the Carboniferous period, world sea-levels were fluctuating in response to the growth and decline of a series of major ice-caps over the continents then clustered around the South Pole. Britain lay in the equatorial region. At times of high sea-level, silt and mud accumulated within the Pennine basin whilst at times of low sea-level, major deltas prograded across the region, their legacy being the thick sandstone beds of the Millstone Grit Group.“
I kind of agree with you, for all intents and purposes these both form course sandstones so in places atleast the rock is a type of Gritstone. That said the term millstone grit also refers to shale!
"Geologists refer to the whole suite of rocks that encompass the individual sandstone beds and the intervening mudstones as the Millstone Grit Group"
I think in the uk when climbers refer to the rock Gritstone they normally specifically mean the rock that people climb around the peak district and a bit further north too in to the yorkshire dales (although there is rock that is rightly classified as gritstone elsewhere too). Its pretty clear the rock you have found isn't formed the same way as typical gritstone and doesn't look the same either.
Party pooper ;)
Down hill racist is still a great route name. Though next you'll be telling us they chipped it
Yes there is all of the Rhinnog/Barmouth Grit in Snowdonia.
It feels the same at least! :)
You should come to C Scotland. I can show you loads of unclimbed esoterica.
I would if i lived there and was writing a guidebook to the area.
Millstone grit does not refer to shale. The Millstone Grit Group contains shale and Millstone Grit (and other stuff), just like the Lias Group contains shale and a limestone commonly known as Blue lias. Group and formation names are often derived from the main lithology within the group or formation.
I think millstone grit is a term for rock that was used for, believe it or not, millstones. Just like limestone is a name for rock used for lime. Hence, if it walks like a duck and quacks like one, then it probably is one. In a technical geological context if you're comparing rock from two dfifferent locations then it gets a lot more complicated. From a climber's point of view it's purely lithology, that's to say its composition, grain size/shape etc. It makes no difference how old it is or where it comes from.
Yeah I forgot to add the 'group' term I realised after posting but hey it was too late to change.
millstone grit geologically is not simply a rock type used for millstones, did you not read my links?
PS that duck looks more like pigeon to me ;)
More info here
The term 'Millstone Grit' was also adopted in South Wales where rocks of similar age and lithology are found though the Millstone Grit series of this region has recently been formally renamed by the British Geological Survey as the Marros Group. The thickest bed of sandstone within it was known as the Basal Grit. This has now been renamed as the Twrch Sandstone. The Farewell Rock was formerly considered to be the uppermost unit of the Millstone Grit series of South Wales though it is now included within the overlying South Wales Coal Measures.
Main article: Marros Group
Anyway as mentioned the group around the Mendips is possibly different to the Marros Group but it appears to have more similarities to it than millstone grit as it was likely formed from southerly flowing rivers from a lateral mountain range across mid to north England/Wales starting around North Wales. Millstone grit was mostly formed from rivers flowing south from a different more northerly mountain range although some rivers did flow north from the more southerly mountain range too.
Well, it says its Millstone Grit in all the local historical/geological books so it will go in the local climbing book as Millstone Grit!!
Local Millstone Grit for local people! ;)
Enjoy its all yours ;)
well......it's actually all Deepstar's!
Ooo this is going to be a fun game.
How many rock types are there,I dont know but it is weired stuff,more research required.
Ah so you dont know what it is yet! Leading me along with your cryptic mystery... Sounds interesting though!
Nice one Deepstar, weve done gritstone, now bored of that.
rusty pegs embedded in a matrix of petrified faeces?
Sounds like heaven!
Coarse not "course", please. I feel the Eastville sandstone may have a gritstone feel to it, as well.
Penant Sandstone - much finer grain size.
Pedant Sandstone -even finer.
That's the trouble with geology. You may get pedantic about what it's called, but what it actually is , is another matter. It may be called Pennant Sandstone (http://books.google.co.uk/books?id=-6gqvAbdS-MC&pg=PA222&lpg=PA222&dq=pennant+sandstone+... but still contain beds of mudstone through to conglomerate. Climbing on conglomerate is not the same as climbing a fine sandstone.
Show us the rock!
I don't know what books your reading but just looking at the rock it clearly not gritstone. It shows no sign of grit. But show all the marks of limestone has anyony done an acid test on it?
I bump in to a local quarry man out walking his dog and he said there is no gritstone around.
Check the local history Marti.I will post a photo shortly.A modern local quarryman will rightly tell you that there is no gritstone quarried on Mendip today,however he would be incorrect to say that it has never been quarried there.I spent many hours visiting museums,reading local history and even had a Profesor of Geology visit the site so am quite certain that Gilson's Slab is Gritstone.
What used to be called millstone grit only 50 miles north is now called twrch sandstone and the rock in the medips is far more similar to that than millstone grit.
However you are right gritstone isn't a name for a specific rock type as such and is just coarse grained sandstone and what you have discovered in the mendips is coarse grained sandstone. There is plenty of similar rock in the wye / south wales area.
UK climbers of course are generally referring to millstone grit when they call a rock gritstone and it seems highly likey this rock in the mendips does differ from that.
Correction what used to be called Basal Grit is now called twrch sandstone and the group in south wales that was referred to as the millstone group group (that contained Basal Grit) is now referred to as the Marros group (and contains Twrch sandstone).
How does that explain the calcite pockets and that it looks nothing like gritstone ( or course sandstone) nice find though.
Do you mean the Quartzite pockets?
I am going to take the samples to Bristol University for identification so should hopefully know exactly what it is soon.
I think some people who are doubting this are getting too hung up on trying to assign their own degree of accuracy to a name that's not supposed to have the level of accuracy they think it does. Anyway, I dug out an old geology book (1977), Geology of the Country around Wells and Cheddar. The Millstone Grit series is present in the area, and the sandstones (the "Millstone grit") are described as having quartz grain sizes commonly around 0.3mm diameter, but ranging up to 3mm, which I think matches what you told me yesterday.
A quote from a local history book."MILLSTONE GRIT AND QUARTZITE" this type of stone was used for grindstones in cornmills.The deep narrow trenches running east to west in ******** **** are where narrow bands of Millstone Grit have been quarried.
Sounds interesting, whatever it is. To repeat marti999's question: could you do an acid test on the rock??
BTW Which was the crag you lost access to when it became public??
Yes, i am trying to trck down some sulphuric acid but i am not spending any money.
sorry i mean hydrochloric acid.
http://www.ukclimbing.com/images/dbpage.html?id=231077 UKC seem to have removed it from the site now,nice of them to tell me!
If your thus inclined you can see the 1:50000 geological map here:
(search for Frome, i cant work out how to copy the link to the location)
Yeah seen that already thanks.
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