the road and tunnel pattern may also have been caused strictly by the act of cutting the gob off the ponty with a shears. A lot more experimenting would maybe clarify these questions.
I speculate that M.F. Christensen "9" slags were gathered from a pot that was stirred in one direction. The gather would have to be hot enough to drip off the ponty onto the roller without any additional spinning of the ponty thereby retaining the 9 pattern. This would explain the many examples with tails created by dripping very hot glass.
The road and tunnels in Johns post were done in the early 1990's. I can't explain exactly how the pattern is created but know my marbles were made by picking up different colored pieces of glass and heating them in a glory hole while spinning the ponty. CAC marbles may have been gathered from a pot but the ponty spun before gobs were cut off onto a rounding machine. The term road and tunnel was used in a pamphlet describing my marbles just because that's what it looked like to me.
a road and tunnel pattern indicates a hand gathered marble. It also indicates the gather is mixed "on the stick" or ponty rather than in a pot like the 9 pattern. You also may be able to tell whether the gathering boy was right or left handed by the direction the road approaches the tunnel.
chris robinson
Yes that marble was made by George Williams. He was a great guy who had a glass factory in Jane Lew, w. Virginia. He gave me a bunch of his older equipment (blow pipes,molds ect. when I visited him by in the 90's.