  We find that dust clouds which eclipse young stars obscure the stellar disc
inhomogeneously. In the particular case of CQ Tau, we find isolated optically
thick structures with sizes $\lesssim0.6R_*$ and derive the typical $A_{V}$
gradient in the plane of the sky, finding it as high as a few magnitudes per
stellar radius. The large extinction gradients and complex structure of the
obscuring clouds lead not only to a noticeable Rossiter--McLaughlin effect, but
also to complex and variable shaping of stellar absorption lines.
