This paper presents a geological application in a virtual immersive environment : the Immersive Geological Pilot. This application allows a user to interactively build a structured geological model and its associated geological evolution scheme (a directed acyclic graph) by setting the various geological surfaces of the model one after the other in reverse chronological order, beginning with the youngest one. This immersive system runs on a workbench where users work directly within a virtual world. The main goal has been to prove that this geological application can benefit from working immersed and from 3D interaction techniques. After introducing the geological application on workstation, this paper describes the immersive version and presents the interaction techniques which have been used for selection, manipulation, navigation and application control. The resulting application in a 3D virtual environment is much more intuitive and ergonomic than the one on workstation.