[ScoochDude]

Please expand on that.

[LukeL]

It is deposited slowly over time either through evaporation of water, over saturation of water or through dissolving of other rocks and moving done stream. It can also be formed from tiny shells and such.

As it is deposited this way many different layers can form which indicated different periods of formation which can be many many years in time. On the rock you can see near the dino print that some layers have either been chiseled or eroded away and the human print goes through these layers.