County halted Walsall's run of five successive home wins, but had looked in trouble when Will Grigg had a sixth-minute shot cleared off the goalline by Alan Judge and the Saddlers went ahead after 29 minutes from a penalty.
County goalkeeper Bartosz Bialkowski fouled Jamie Paterson in a corner of the box and after a delay while a flare thrown on to the pitch from the visitors' end was cleared, Grigg coolly scored his 11th goal of the season from the spot.
But the visitors equalised in the 65th minute when substitute Arquin stabbed the ball home after a cross from Jamal Campbell-Ryce unsettled the home defence.
Smith said: "It was a horrible game on a horrible pitch, but we had opportunities to go more than one-up in the first half.
"But they were the better team in the second half, although we should have had another penalty for a foul on Craig Westcarr.
"It shows how far we have come that we are disappointed with a draw against a side like Notts County."
Smith added: "I think it was an honest score from two honest teams. We are a point better off than we started the day."