Filling in a cliffside

[pred_alien07]

so i have this problem with the cliff is to small to fill in and i dont know how to get it to fill in

[synntax33]

If you drop dirt at the base it will raise the ground level when it decays and eventually you can level it out using surveying.

[The_Blode]

there's a few terraforming related hotkeys to keep in mind.
with dirt you can ctrl+shift+ right click to drop it from the center of a tile rather than the corner, could help possibly