Slices from Figure 3 (highest confidence sample), but zooming in at the young populations toward the Sagittarius Arm, at the age ranges of 7–7.2, 7.2–7.4, 7.4–7.7, and 7.7–8 dex. Black lines show the location of the Sagittarius and Scutum Arms from Reid et al. (2019). Bottom-left plot shows the kernel density estimate of the distributions of the populations that can be associated with the Sagittarius Arm relative to the spiral arm trace from Reid et al. (2019) as a function of age, limited to the highest confidence sample. Bottom-middle and -right plots show the distribution of velocities as a function of age for this sample.