  We report the progress on our analysis of two deep XMM observations in the
areas of Hubble Deep Field-North and the Groth-Westphal Strip field. We present
the source detection method, Monte-Carlo simulation on source detection, and
our preliminary Log N -- Log S relations. Comparing these two fields and other
fields in literature, we find up to 30% variations in number counts near our
flux limits, which is most likely to be due to cosmic variance. This serves as
a pilot study for a more systematic investigation. The nature of the X-ray
sources in the Groth-Westphal field is also discussed in terms of hardness
ratios, morphology and spectroscopic properties.
