Define the following conventional signs and symbols and explain in brief.

(i)

(a) Depression — A hollow created on the top of mound or dune in sandy area, formed by blowing away of sand by the wind is called depression.

(b) Stony waste — The land which is mostly covered with rock boulders and stones and where cultivation is not possible. It is shown as a white patch on the map.

(c) Sheet rock — A region which is mostly covered by a sheet of rock is called sheet rock. It is shown in white and is printed on the survey sheet.

(d) Rock-out-crop — Subsoil is exposed in such areas and cultivation is not possible. It is printed on the survey sheet.

(e) Surveyed tree — It serves as a prominent survey point, shown in black.

(f) Embankment — A bank or mound constructed along a tank or artificial lake to prevent flooding is called embankment. It is generally a cemented structure.

(g) Stone quarry — It is the underground quarrying for stones. Its presence indicates the occupation of the people in the region. It also shows the trade possibilities.

(h) Meander — A bend in the river flowing through a flat land or plain during its middle stage is called meander.

(ii)

(a) A Ridge — A long, narrow highland with edge along the top of hills or mountains is called ridge. The contours of a ridge are elliptical or elongated in shape. It is called watershed or water divide as it divides two drainage systems.

(b) Spot height — Spot height is the height of a particular point measured and is shown on the survey map as .240. It means that the height of that particular point is 240 metres above sea level.

(c) Relative height — 3r. besides a river bank, tank with embankment or sand dune shows the relative height between top and bottom. Hence, it should be explained as the relative height of the embankment of the tank is 3 metres.

(d) Fire line — A clearing made in the forest to prevent spread of fire is called Fire line.

(e) Causeway — A raised road or platform across a stream is known as Causeway. A stream having a causeway is motorable during dry season. Hence too many causeways indicate scanty or seasonal rainfall.

(f) Brackish — Brackish written beside a perennial lined well indicates that the water of the well is salty, and not fit for irrigation or drinking.

(g) Overhead tank — It is a big water container made on elevated structure for storing water. The stored water is meant for public supply.