Compact and leveled limestone bedrock creats a biological environment known as Alvar. According german wikipedia one more criterion shall be that the limestone rock was more or less planed by the ice of the ice age. Often scratches of those glacier works can be seen on the surface of the "pavement".

More about Alvars:
english - en.wikipedia.org/wiki/Alvar
deutsch - de.wikipedia.org/wiki/Alvar_(Landform)