Picked up by the Wayside.
--Lieut. Baptist, of the night police, carried before the Mayor yesterday morning a mulatto girl, about nine years old, called Frances, who had been picked up in the streets of Fredericksburg some weeks ago by a cyprian, who had her in custody as a servant. Not knowing whether the girl was slave or free, the Mayor ordered her into the custody of Lieut. B., to be taken care of till something could be heard from Fredericksburg in regard to her.