The snail shell symbolizes the perfection of nature’s creativity, which is also echoed in mathematical fractals (repeated patterns). The spiral shape of the snail shell is symbolic of the labyrinth.
Psychological / Emotional Perspective:
From a psychological point of view, the snail suggests steadiness and self-containment. To be moving at snail’s pace suggests direct planned, careful movement.
Everyday Material Aspects:
The snail appearing in dreams may engender, because of its sliminess, a feeling of repulsion in some people. It does, however, also represent vulnerability and slowness, along with the type of apparent rootlessness seen in the Wanderer.
You might also like to consult the entries for Labyrinth, Shell, Spiral and Wanderer.