The Ceffyl Dwr is a water horse from Welsh forklore, similar to the Scottish Kelpie.
The Ceffyl Dwr is said to inhabit mountain pools and especially waterfalls. The Ceffyl Dwr appears solid but then can evaporate into the mist.
In one form of the legend the Ceffyl Dwr, as a horse, leaps out of the water to trample and kill lone travellers but a more common telling of the legend is that the Ceffyl Dwr will entice an unwary traveller to ride him and then fly up into the air. Once in the air, the Ceffyl Dwr will evaporate, dropping the unfortunate rider down to his (or her) death.
The cache is not at the posted coordinates. To find this cache, figure out the final coordinates from the following (assume N 26 27 and W 081 33);
chwech chwech saith
saith pedwar pump