Tuesday, August 17, 2010

Stone Story. Segment Two. Part 2

Unlike Rhonda, the circumstances that shaped Myron were things he wanted to forget. He had spent many millennia milling around, just below the earth's surface barely existing as a large sandstone deposit known as ' millstone grit ', back in the Namurian age. It was a very dull geological period of his life.

Myron told Rhonda,

"The Pennines just seemed cold and dark back then. Dark seams of coal below, piles of earth above, and nothing but formless sandstone in every direction.

"I had no identity back then, just part of a huge faceless mass of bedrock. I wasn't near enough to the surface to be where the interesting things were happening. And too, I wasn't going out with anyone back in those Carboniferous days, about 350 million years ago", but then Myron wondered if he was dating himself.

Many million years later, (probably during the time Rhonda was managing to scrape her way across Scotland) a lot of the sandstone bedrock around Myron was exposed. A long time after that, somewhere back in the early 1800's he, along with a lot of other grit material, had an opportunity to get quarried and shaped by humans into massive sandstone 'wheels' to be used as millstones.

"Extracting a whole millstone from a rock outcropping was basically a 'hit or miss' procedure. You either got the drill or you didn't. Back then only the stones that showed real grit made it in one piece through the extraction process."

Myron went on to explain that stone used for making a millstone could not have any lines of weakness which could cause it to crack as it was being removed from the bedrock. In order to quarry millstones from a deposit of millstone grit, a narrow circular groove was first made outlining the shape of the millstone to be taken from the rock. Deeper cuts were chiseled into the circle and these were pegged with wedges made of oak. Water was then poured on the wedges causing them to swell and so eventually the wedges split the stone, facilitating its extraction as a single piece from the surrounding rock. The middle hole was usually cut on site. This method of quarrying millstone left large perfectly round hollows in the rock surface, or sometimes just a shallow circular groove in the bedrock, if the stone cracked the wrong way before it was freed. Stones frequently cracked during the arduous quarrying process or later when they were bored. Myron had ended up in his original 'pie shape' (later to become more pyramid-like) when he broke off from one of these flawed millstones.

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