General Information and Warnings
Please note, it has been assumed you will have visited the earthcache Cwmorthin Geology Trail 1 (GC6JBEN) before you visit this one. If not, the waterfall has been given as a waypoint for you to visit it, to allow you to answer question 1.
Here at Cwmorthin you will find a stunning glacial valley but geologically it can be confusing due to the vast amounts of slate mining and surface quarrying that have taken place here. The earthcaches on this trail focus on both the original glacial features of the valley, and also the interesting slate that has been exposed from underground by the workings. Always remember that the huge piles of slate you will frequently walk over and past were not placed here naturally, this is all the work of man. As you walk around, try and keep an image in your mind of how the valley would have looked before the slate was quarried.
The Rhosydd Geology Trail follows the track up the south side of the lake and back around to Plas Cwmorthin, a former quarry managers mansion. It extends a little further on a less used path that can be boggy in places, the rangers have asked that you return via the same route from the farm, please don't try and cross the boggy area between the farm and the old mines. This trail is generally further away from the mines and spoil heaps but you will pass old buildings that may be unsafe and there could be other hidden dangers - please take appropriate care. Also be aware that slate can have a very sharp edge and can cut very deeply, so please treat this area with the respect it requires.
Information about the Valley Head Falls
This is the second and final waterfall, or series of waterfalls, we have included in our earthcache trail at the Cwmorthin valley. It's almost a stream flowing down the valleyside forming a series of waterfalls, but the waterfalls are so constant some would believe it is reasonable to classify the whole feature as a waterfall. The dictionary definition of a waterfall is "where water flows over a vertical drop or a series of drops in the course of a stream or river". The first waterfall you probably visited (Cwmorthin Geology Trail #1) shows you the water as it exits the valley at the bottom, and we have included this one because it shows the water as it enters the valley at the top and is so very different.
Generally speaking, when a waterfall forms closer to the source of the river, the river course takes it over resistant bedrock and erosion happens slowly, while downstream the erosion occurs more rapidly. Streams become wider and shallower just above waterfalls due to flowing over the rock shelf, and there is usually a deep area just below the waterfall because of the force of the water hitting the bottom. Waterfalls normally form in a rocky area due to erosion. The diagram below illustrates the general classifications of waterfalls.
Logging Requirements (Questions to Answer)
Please e-mail (or message) me the answer to the questions via my profile. I do read all answers and try to reply to them all; I may not reply immediately so please do not wait for a reply before posting your find. Ideally, please send your answers at the same time you submit your log, or within a few days of your visit. I do check answers have been sent for every log, if you do not send answers within a week your log may be deleted. You are not expected to have any previous geological knowledge, your best attempt at the answers is all that is required.
1. Compare this waterfall with the one you visited at the bottom of the valley (Cwmorthin Geology Trail 1, or visit provided waypoint). Can you explain the key reason for the difference in the erosional force it possesses here?
2. Do you believe the feature meets the definition to be classed as a single waterfall (in the early stages of evolution), or do you believe it is a stream with a number of small waterfalls?
3. Given your previous answer, which of the waterfall types from the diagram above is this one?
4. The waterfall here is clearly not a slide, but as the water is flowing down a steep valley side, theoretically, it would make more sense if it was one. Why is it not a slide? Why does the stream take the route that it has chosen? Do you think it will ever become a slide?
We always like to see photographs of you and/or your GPS device with the geological features - plus this also provides additional proof of your visit, so please include one with your log if you wish.
This cache has been produced especially for the
