I followed Chance's directions and before too long was at the stone in question. The strange thing is it ‘felt’ like you were walking in the ‘wrong’ direction walking away from Avebury. The Avenue ‘feels’ right when walking towards the circle/henge – make of that what you will?
As stated, the marks are on the fence-side of the stone, about 1 foot above the ground.
I spotted 3 fairly deep groove lines and possibly another 3 slight grooves.
The grooves are not that obvious unless you are looking specifically for them.
Worth looking out for if walking along the Avenue.
Half way down the restored West Kennet Avenue, The inner (eastern) face of Stone 19b of the West Kennet Avenue bears near the base a group of small but typical marks of the kind thought to have been produced by the grinding and sharpening of flint or stone axes.
A few simple notes, on how to find this stone.
From the Red Lion pub, cross over the road to the Southern or Sun circle.
Walk up to the portal stones and follow the path to the right, close to the wire fence and the trees.
Take care on this stretch as the tree roots can be tricky under foot.
Look carefully and you will find the broken stump of Avenue Stone no.3. Go through the gate and watch for traffic as you cross the road.
Go through the gate and pass of Avenue stone No.4, The Bison.
Walk further down the Avenue, through the concrete plinths. You won't reach any more sarsens until you get to Stones 13A and B. Count down the stones, 14A, 15 A and B. At number 16, the Avenue jumps into the road and 16A is buried beneath the asphalt, leaving 16B alone. Stones No.17A and B are gone for good but 18A sites right next to the fence, with the stump of 18B on the other side of the road. The Stone in front of you is now 19B. The inner face nearest the fence shows the polissoir marks, a hollowed out flat surface and several grooves.
Other items of intersest include part of a polished patch on Avenue Stone 32a, above the broken part on the damaged face and more diffuse smoothed areas also occur on Stones 24 and 31 of Avebury's Outer Circle.
Smith, I. F., Windmill Hill and Avebury: Excavations by Alexander Keiller 1925-1939, London, OUP, 1965.
Section 5. ARTIFICIAL MARKINGS ON STONES - Page 223
Far more easy to find than the Polisher but lacking the ambience of the downs.