Molecular clouds in the extreme outer Galaxy between $l=34.75^{\circ}$
  to $45.25^{\circ}$
  We present the result of an unbiased CO survey in Galactic range of
34.75$^{\circ}\leq$l$\leq$ 45.25$^{\circ}$ and -5.25$^{\circ}\leq$b$\leq$
5.25$^{\circ}$, and velocity range beyond the Outer arm. A total of 168
molecular clouds (MCs) are identified within the Extreme Outer Galaxy~(EOG)
region, and 31 of these MCs are associated with 13CO emission. However, none of
them show significant C18O emission under current detection limit. The typical
size and mass of these MCs are 5~pc and 3$\times$10$^{3}M_{\sun}$, implying the
lack of large and massive MCs in the EOG region. Similar to MCs in the outer
Galaxy, the velocity dispersions of EOG clouds are also correlated with their
sizes, however, are well displaced below the scaling relationship defined by
the inner Galaxy MCs. These MCs with a median Galactocentric radius of 12.6
kpc, show very different distributions from those of the MCs in the Outer arm
published in our previous paper, while roughly follow the Outer
Scutum-Centaurus arm defined by Dame & Thaddeus 2011. This result may provide a
robust evidence for the existence of the Outer Scutum-Centaurus arm. The lower
limit of the total mass of this segment is about 2.7$\times$10$^5$ $M_{\sun}$,
which is about one magnitude lower than that of the Outer arm. The mean
thickness of gaseous disk is about 1.45$^{\circ}$ or 450~pc, and the scale
height is about 1.27$^{\circ}$ or 400~pc above the $b=0^{\circ}$ plane. The
warp traced by CO emission is very obvious in the EOG region and its amplitude
is consistent with the predictions by other warp models using different
tracers, such as dust, HI and stellar components of our Galaxy.
