Constructed in 1824 as an earth dam by the Warrington and Stockport Turnpike Trust (and now carrying the A56) over a pool and stream in the valley below St. Mary's church, Lymm dam was built to help avoid congestion in the village. A lake now known as Lymm dam soon grew behind it. More information on the history of the dam can be found here or here (with map).
The wooded area surrounding the dam is now popular with walkers, responsible dog owners, anglers, bird watchers, cyclists and horse riders, enjoying the Oak and Beech woodland, and variety of wildflowers and wildlife.
Surrounding the dam are many areas of exposed rock, which have been identified as sandstone, a sedimentary rock formed over a period of millions of years by the compression of many layers of tiny grains of sand, which settle over time either from water (bottom of a river / lake / sea) or on land (i.e. a desert), and are then compressed by the weight of overlying layers. The sandstone surrounding the dam was created during the permo-triassic period (i.e. towards the end of the Permian geological period, and the start of the Triassic geological period), and is around 250 million years old.
The sandstone at the northern end of the lake is known as Helsby sandstone, which is known for its red-brown colour (certainly more red than that of the layer of Wilmslow sandstone which lies underneath, and is visible if you move further north, through the village of Lymm and into Slitten gorge beyond), which was primarily formed by sedimentation from streams and rivers.
This particular earthcache is located on a rocky bluff below St. Mary's church and is of special interest as one of only two examples discovered in the UK of formations known as "Nye Channels" and "Scallops" (The other location is at Thurstaston Hill on the Wirral).
Nye Channels are the deep cuts found in the rocks, and Scallops are the rounded steps found in the vertical sections. These were formed around 10-13,000 years ago at the end of the last glacial period (known as the Devensian glaciation), when Cheshire was covered with ice - under which flowed meltwater containing rock and soil deposits, eroding the sandstone in this unique way. The Nye Channels and Scallops were formed where the water flow was the greatest.
To claim this earthcache you must send me an e-mail with the answers to the following questions;
1) What direction do the majority of the Nye Channels run (e.g. North-South).
2) What is the approximate depth of the deepest channel.
3) OPTIONAL - Upload a photo of yourself with your GPS by the lake in front of bluff.
Please note, you do not need to send the e-mail before logging a find, however logs without a corresponding e-mail, or logs containing the answers may be deleted.
Please do not damage the formation, leave it as found for others to enjoy.
Thanks to Tim Baker (Area Ranger, Lymm & Thelwall) for kind permission to list this earth cache.
Car parking can be found at N53 22.588 W002 28.632.
This earthcache can be accessed via bus (No's 5, 6, 37, 37a, 38 & 47).
This earthcache is pushchair & wheelchair accesible, via a path from N53 22.686 W002 28.753.