The stone mushrooms of Beli Plast are just a little larger than your average shroom. The biggest is over three meters in height and they were formed thousands of years ago. They are made from lime stone which can be eroded by water. Over many centuries the water of a lake or a river can undercut limestone – and sometimes it can have bizarre results, especially when the water responsible for the erosion has disappeared. Alone like mushroom shaped islands it is little wonder that supernatural tales spring up around them.
It was not until the nineteenth century that the science behind the mushroom stones – or wave stones as they are sometimes called – was verified. Then it was discovered that this strange natural phenomenon was the result of huge limestone boulders which have been exposed to water for frequent and prolonged intervals. It was also discovered at that time that they were what are now known as glacial erratic. That is they are huge boulders that have been pushed downwards (geographically) by the sheer force of a glacier and so may not even have any similarity to the stone where they eventually remained.
Where the mushroom head is visible is the actual point of where the water of a lake once reached. The water never went higher than this point and below it, as the water retreated and flooded over the millennia the strange ‘stalk’ of the mushroom formed. Once the water had receded completely the mushroom stones are left as a permanent – if odd – reminder of the water that was once there. Stones like these in Bulgaria are found in many places, with a number of them near to lakes. These stones in Beli Plast mark a lake which has, however, long since gone.
Limestone has a very long history – it goes back three hundred and fifty million years to a period of Earth’s history known as the Devonian. At this point huge swathes of land in Europe were covered by a warm but shallow sea. Over vast periods of time a thick layer of lime rich sediment was deposited at the bottom of this sea – it was this carbonate which gives the Lower Carboniferous era its name. The thick layer of sediment would have started out like a mushy liquid but then over millions of years it was compacted by additional layers of material on top of it and it became hard – rock hard. So it was that it eventually became limestone.
When shifted by a glacier, a boulder of limestone can end up many miles away from where it formed. Then, when exposed to the air at last it can find itself at the edge of a lake and covered up to a certain height by water. As limestone corrodes in water that part of the boulder underneath the lapping waves (abrasively, persistently and tenaciously wearing away the limestone) will remain and become what is known as undercut. That is the stone beneath it is worn away and eventually the boulder will look like a mushroom. Think of eating an apple around the middle but not at the top and bottom and what is the resulting shape? You get the idea.
Many people, though, prefer the story that the Bulgarian locals tell. They call them ìmantarnayaî which translates as stone mushrooms but the legend, although frightful has resonated for centuries when told to travellers. At dawn the four daughters of the local charcoal burner, by name of Radoun, left the protection of the fortress of Perpericon. They were water carriers and their daily task was to go the local river to collect the water needed for their father’s livelihood.
One of the four daughters, Gyusha, spotted an invading army and the girls were able to run back and give their fortress warning. However, after a week of siege, traitors opened the gate and let the army of the enemy in. The four sisters were captured but managed to escape and tried to flee to a local monastery. However, one of the invading army, Omur, pursued them and with a vicious blow, severed Gyusha’s head. The miracle happened and she turned in to a beautiful stone mushroom. Omur killed the remaining three who then, successively, turned to stone as well.
Convinced the place was cursed, Omur tried to flee. However he was at the precise moment turned in to rock himself. Perhaps it could be the morning dew, but older residents of Beli Plast swear that in the mornings, tears can be seen dripping from the stones. The tears of the four sisters.