I wonder what "pebbles" means in this context.
"Mr Cripples's pupils, who were by this time coming to school,
desisted from their morning recreation of cuffing one another with
bags and books, to stare with all the eyes they had at a stranger
who had been to see Dirty Dick. They bore the trying spectacle in
silence, until the mysterious visitor was at a safe distance; when
they burst into pebbles and yells, and likewise into reviling
dances, and in all respects buried the pipe of peace with so many
savage ceremonies, that, if Mr Cripples had been the chief of the
Cripplewayboo tribe with his war-paint on, they could scarcely have
done greater justice to their education."