A method of forming a wall structure (10) that replicates a wall formed by nature. Methodology for fabricating the wall structure (10) includes pouring a first concrete mixture (12a) into a substantially vertical form (50) which is constructed as a channel (56) within a generally elongate mound (54) of naturally occurring material and thereafter permitting a top surface of the mixture to assume a non-level configuration. Preferably, a joint forming material (22) is placed on the top surface of this first concrete mixture (12a). In like manner, a second concrete mixture (14a) is poured on top of the first layer (12) and a joint forming material (22) is included. Additional layers (16, 18, 20) can be added, with the concrete mixtures preferably including decorative additives (26, 28) that are exteriorly visible. After form (50) removal by removing the mound (54), the entire wall (10) or individual layers (12, 14, 16 ,18, 20) thereof can be subjected to an exterior treatment to enhance appearance.