By chris 論 [GFDL or CC BY 3.0 ], from Wikimedia Commons
A petrifying well gives objects a stone-like appearance. If an object is left into such a well for a period of weeks or months the object acquires a stony exterior. Notable example of petrifying well in England is the spring at Mother Shipton’s Cave in Knaresborough where objects left suspended in the calcium-rich water are gradually turned to stone. For many centuries, locals believed that this petrifying well was cursed by the devil . The fact that the side of the well looked like a giant’s skull fueled their fears that they too would be turned to stone.The Knaresborough petrifying well was first opened to the public in 1630 and still amazes visitors to this day.
By Uncool Eddie [CC BY-SA 3.0 or GFDL], from Wikimedia Commons
By Immanuel Giel – Own work, CC BY-SA 3.0, Link
By Uncool Eddie [CC BY-SA 3.0 or GFDL], from Wikimedia Commons
By Immanuel Giel – Own work, CC BY-SA 3.0, Link
By Dr Neil Clifton, CC BY-SA 2.0, Link
By Uncool Eddie – Own work, CC BY-SA 3.0, Link
e MORFES 
It’s amazing what nature does. As if I were a sculptor of the unknown. Your photos are optimal quality.