Candidate volcanic vents, lava flow-related channels, and teardrop-shaped features associated with smooth plains deposits in Mercury's northern hemisphere. (Upper left and right) Image and sketch map of the assemblage of volcanic flow-related features. Blunt arrows, flow-front-like embayment; long arrows, teardrop-shaped hills (TH). (Lower left) Pits interpreted as source vents. (Lower right) Teardrop-shaped hills and channel interpreted to be formed by lava erosion.