  The technique of determining the acoustic location of layers of sharp changes
in the sound speed inside a star from the oscillatory signal in its frequencies
is applied on a solar-type star, the CoRoT target, HD49933. We are able to
determine the acoustic depth of the second helium ionisation zone of HD49933 to
be 794 +55/-68 seconds. The acoustic depth of the base of the convective zone
is found to be 1855 +173/-412 seconds where the large error bars reflect the
ambiguity in the result, which is difficult to determine with present precision
on the frequencies because of the intrinsically weak nature of the signal. The
positions of both these layers are consistent with those in a representative
stellar model of HD49933.
