  The magnetization of three high-quality single crystals of
YBa$_{2}$Cu$_{3}$O$_{6+x}$, from slightly overdoped to heavily underdoped,has
been measured using torque magnetometry. Striking effects in the angular
dependence of the torque for the two underdoped crystals, a few degrees above
the superconducting transition temperature ($T_c$) are described well by the
theory of Gaussian superconducting fluctuations using a single adjustable
parameter. The data at higher temperatures ($T$) are consistent with a strong
cut-off in the fluctuations for $T\gtrsim1.1T_c$. Numerical estimates suggest
that inelastic scattering could be responsible for this cut-off.
