The disk of the Milky Way beyond the solar circle is not open to simple

interpretations. In short, it is a mess. From observations of interstellar

gas it is clear that the disk has both a warp and a flare.

The stellar component is riddled with stellar over-densities and/or streams,

the largest of which is the Monoceros stream. It is unclear whether gas

is in-falling and still building the outer disk, whether the distribution

of dark matter inflates the outer disk, if interactions with satellite

galaxies are perturbing the disk or if disrupted satellites are adding

to the disk. It is possible that all of these effects are contributing.

What is clear is that the outer disk of the Galaxy holds many clues as to

how galaxies form and evolve.



   Studying stellar populations in the outer disk is useful but currently has

limitations because spatial and kinematic distributions are not uniquely

described by the various Galactic models. I will discuss our current

attempts at helping to constrain properties of the outer disk using

spectroscopic analysis of A-star samples. Most of the talk will be dedicated

to our analysis of chemically peculiar A-stars in the SDSS DR8 sample and

whether the distribution of these stars indicate that the Monoceros stream

contains ancient blue stragglers or younger A-stars. The latter conclusion

might suggest that the stream is a component of disk of the Galaxy, while the

former might indicate dwarf disruption. I will conclude the talk by showing

our current work on the Canis Major Over-density and our future goal to explore

dust distribution in the disk using A-stars