The main difference between geography and geology is that geography is mostly dealing with the physical overall shapes of the land. Geology is a science that is interested in how the land got into the shape it did.
Geology is mostly about what the ground is made up of from a natural perspective. What kind of rocks it contains and how those rocks or layers of rocks got there.
Geography is mostly dealing with mapping the extent of landforms, how far rivers are, how long mountain ranges are, how long the coast line is. This is often from the perspective of people or culture.
The ending of the word (suffix) also is an indication of the differences between geography and geology. _graphy means to draw or record. In other words, 'to draw the land' and _ology meaning 'to find knowledge of the land'