Urchin’s Kitchen Earthcache LOCATION: Eight miles west of Northwich START: A54 Gresty's Waste car park, half mile beyond A556 junction (Grid reference SJ540687) DISTANCE: Three miles GRADE: Easy TIME: One and a half hours MAP: Explorer - Northwich & Delamere Forest History - from an article by Joan Fairhurst, 2003
The Formation of Kelsall's Landscape Kelsall lies in a nook on the south-west facing escarpment of the Mid Cheshire Ridge. Indeed the name Kelsall may well be derived from Middle English (1100-1500 AD); Kells Halh meaning 'Nook of land of a man called Kell'. Investigating the origin of the nook and the underlying sandstones requires significant time travel. Kelsall gap lies at 125m, with Pale Heights (176m) and the Yeld (157m) to the north and Primrose Hill (158m) to the south. There are parallel but smaller nooks at Boothsdale and Willington.
The broad landscape is shaped by Permo-Triassic sandstones and a series of parallel faults running NE/SW. During the Permian, some 250 - 286 millions years ago, this part of the earth's crust was stretched causing faulting and subsidence. The strong red colouring in the local rock is due to iron oxide, coating round the sediment grains, and indicates an origin in desert conditions.
The Helsby sandstone formation is thought to be braided stream deposits from the Variscan mountains which, in the Triassic (250-213 million years ago), rose between present day Dorset and Brittany. At the time this part of the continental land mass is believed to have been much nearer the equator. The Triassic period ended in this locality with the incursion of the sea and the deposition of Cheshire's salt beds to the east of the central ridge. Today natural rock exposures occur notably at Urchin’s Kitchen in Primrose Hill Wood and at Hanging Stones on Old Pale.
In addition there are numerous quarry faces and road cuttings demonstrating the distinct layers of deposition in the sandstone also featured in local walls and cottages. Substantial loose rocks have been moved by ploughing - especially across Organsdale. Some of these, however, are not local sandstone and arrived here by movement of vast ice sheets from the north. Whilst the existing rock formations may have developed beneath later deposits, the influence of glaciation up to 1000m thick (25,000 to 10,000 years ago) has been immense.
The erosion would be exaggerated along the existing geological faults leading to the nook formations we see today. The force of laden melt waters has carved out features like the Urchin’s Kitchen and overlain the bedrock with drifts of sands and gravels together with occasional large boulders. Westward from Kelsall the Cheshire plain with its sub glacial till provides very different soil conditions - the boulder clays. Northwards the Mouldsworth Gap at 55m has been the most significant channel for braiding melt waters. Here it seems that sands and gravels were deposited around stranded blocks of ice giving rise to the undulating landscape of Delamere with its peaty hollows.
From Wikipedia, the free encyclopedia - The Mid Cheshire Ridge is a range of low sandstone hills which stretch north to south through Cheshire in North West England. The ridge is discontinuous, with the hills forming two main blocks, north and south of the "Beeston Gap". The main mass of those to the south are known as the Peckforton Hills; the larger group of hills to the north do not have a collective name. The ridge acted as something of a barrier to the passage of Irish Sea ice during the last ice age and its hills are etched with numerous glacial meltwater channels, many of which formed subglacially.
Particularly spectacular examples are those at Urchin's Kitchen in Primrosehill Woods and at Holbitch Slack near Cotebrook A subglacial meltwater channel is a channel beneath an ice mass, like ice sheets and valley glaciers, roughly parallel to the main ice direction.
These meltwater channels can have different sizes, ranging from very small channels of a metre deep and wide to big valleys which can be up to a kilometres wide. The dimensions of these channels are regulated by several factors, like: temperature, meltwater volume, debris content in the water, ice wall closure rates and squeezing of fluidized sediment (Menzies, 2002). In the scientific literature three forms of sub glacial melt water channels are commonly mentioned. 1. The first type of channels is the R-channels (Röthlisberger, 1972). These are semi-circular channels cut upward into the ice. The balance between channel enlargement by viscous heating and closure by ice deformation when the channels are water-filled reflects their size and water pressure. 2. The second type mentioned is the H-channels. These channels are broad, flat channels cut upward into the ice that tends to follow local bed slope. Such channels form where water flows at atmospheric pressure beneath thin ice and on steep down glacier bedslopes. 3. The last type, the N-channels (Nye, 1973), are incised into bedrock, perhaps suggesting long-term channel stability under some alpine glaciers.
To log this Earthcache please email the answers to the following questions to the cache owner via GC.com.
PLEASE DO NOT PUBLISH YOUR ANSWERS IN THE LOGS Urchin’s Kitchen Information Board and signpost are available at
N53 12 324 W002 41 350
1. What type of deposits were left by the glacial melt ?
2. How many different types of ice pebble can be found along the trial? Can you name three types of ice pebble?
3. Having read that the Ice travelled from the Irish Sea (S.E.),using your gpsr establish which direction the gorge runs and explain why you think it conflicts with the direction of the Ice flow ?
4. How wide is the gorge at GZ from JS1913 to the large rock on the opposite floor (see photo’s)?.
5. A photo on your found log is now a logging requirement (EarthCache guidelines) anyone logging a find without a photo of you or your GPSr visiting the Gorge will have the log deleted.
Please ensure that you meet the guidelines for logging your find Proof that you have visited the cache at the same time as you submit your find log is required. Failure to follow these simple steps could result in your log being deleted within 24 hours of it being posted. You will of course be welcome to re-log the cache. Congratulations to BIG ISH on being First to Complete this Earthcache.