some where, sometime i read, cobble stones are dressed (shaped) stones with a rounded crown. the top of the stone is about 6 inches (15cm or so) in diameter, and rounding.

belgium paving blocks are bigger (almost twice the size) and brick shaped.

they are smoother too. they still give horses traction--though not as much as cobble stones.

(they are smoother than cobble stones, but still bone jarring, even in a car with rubber tires and a good suspension system!)

there are still streets (in tribeca--ie, just a few blocks north of the WTC site) that have not been paved over.

Residents like them, because they inhibit speeding.