  We show that for any $\alpha\in (1/2,1)$ the number of lattice points
belonging to an arc of length $R^{\alpha}$ of the circle of radius $R$ centered
at the origin is not uniformly bounded in $R$, which disproves the
corresponding conjecture of Cilleruelo and Granville. We also give certain
generalizations of this fact and estimates for the $L_4$-norm of Gauss sums.
