Here is an interesting little spot. I was walking along the tracks through the upper reaches of the credit valley recently and noticed a stream pouring out from beneath.
Going down to investigate I discovered a substantial ribbon of water rushing from an arched tunnel of whirlpool sandstone. There had once been sandstone mines in this area and I have always wondered as to exactly where they were. Nt having any light source with me I felt my way up the tunnel until I was in near total darknes. There was a heck of a roar from somewhere beyond. Water was falling from above. Further down the tracks we found a small lake with a pipe at surface level down which the water dropped.
The guy down at the end of the tunnel is my father, he also likes checking out such unusual features.