  We investigate the three-neutrino mixing scheme for solving the atmospheric
and LSND anomalies. We find the region in the parameter space that provides a
good fit to the LSND and the SK atmospheric data, taking into account the CHOOZ
constraint. We demonstrate that the goodness of this fit is comparable to that
of the conventional fit to the solar and atmospheric data. Large values of the
LSND angle are favoured and $\sin^2(2\theta_{\rm LSND})$ can be as high as 0.1.
This can have important effects on the atmospheric electron neutrino ratios as
well as on down-going multi-GeV muon neutrino ratios. We examine the
possibility of distinguishing this scheme from the conventional one at the long
baseline experiments. We find that the number of electron neutrino events
observed at the CERN to Gran Sasso experiment may lead us to identify the
scheme, and hence the mass pattern of neutrinos.
