Slices of Galactic latitude versus radial velocity integrated over 3° in Galactic longitude at the edges (top, bottom) and the center (middle) of the Galactic supershell. Colored dots mark the positions of the dust clumps, and white crosses mark the positions of clouds identified by the CO(2–1) pointed observations that are not associated with the dust clump. The background image shows the corresponding H I integrated intensity from the GASS survey (McClure-Griffiths et al. 2004). The contours mark the CO(1–0) emission from Dame et al. (2001) at levels of 5σ, 7σ, and the 10th, 30th, 50th and 70th percentiles. The spiral arms as determined in the present work and the position of the local emission are marked by the colored solid lines. Cyan: local emission; green: Perseus arm; red: outer arm.