What is indicated by tick marks on a contour map?

The presence of tick marks on a contour map indicates depressions in the land. These tick marks, often referred to as hachures, point towards lower elevations and help to visually represent features such as sinkholes, craters, or other types of depressions. In a contour map, each contour line represents a specific elevation, with closer lines indicating steeper terrain. The addition of these tick marks distinguishes a depression from the surrounding elevated land, making it easier for map users to interpret the topography accurately.