The exogenic forces include climatic, erosional and depositional agents which work on the earth’s surface. Climatic agencies such as heat, rain and wind which work through seepage and motion of air to dissolve, disintegrate and dislodge the materials.
The phenomenon of wearing down of relief variations of the surface of the earth through erosion is known as gradation.
The endogenic forces continuously elevate or build up parts of the earth’s surface and hence the exogenic processes fail to even out the relief variations of the surface of the earth.
The endogenic and exogenic forces causing physical stresses and chemical actions on earth materials and bringing about changes in the configuration of the surface of the earth are known as geomorphic processes.
Diastrophism and volcanism are endogenic geomorphic processes. Weathering, mass wasting, erosion and deposition are exogenic geomorphic processes.
Any exogenic element of nature (like water, ice, wind, etc.,) capable of acquiring and transporting earth materials can be called a geomorphic agent.
When these elements of nature become mobile due to gradients, they remove the materials and transport them over slopes and deposit them at lower level. Geomorphic processes and geomorphic agents especially exogenic, unless stated separately, are one and the same.
All the movements either within the earth or on the surface of the earth occur due to gradients— from higher levels to lower levels, from high pressure to low pressure areas etc.
