A general comment expressed at a user forum (Bélanger/Moore 1999 [PDF, 60.8 kb, viewer]) carried out at the beginning of this project, was that, in urban or environmental studies, it is more important to know the nature and characteristics of rock formations than their age or position in the stratigraphic column. Consequently, a Rock Type Map ( Maps - GeoServ ) was produced from the Regional Synthesis which groups bedrock formations according to the properties of the rocks rather than on stratigraphic and age relationship. In this case, formations having similar genesis and properties are grouped together even though they are considered as separate geological events; similarly, two consecutive rock sequences are not necessarily reported in chronological order if they differ in nature. Paleozoic rock formations are reported in the legend in chronological order, when possible, but the priority is placed on the nature of rocks. Precambrian rock formations are reported according to rock types, based on their genesis, using the same approach as for the Regional Synthesis.

A rock type map is however of limited use in environmental studies if not accompanied by a comprehensive legend providing detailed information on the characteristics and properties of the rocks, and a link to each formation within each rock type. Consequently, the Rock Type and Regional Synthesis maps are linked to an online database (Download file [PDF, 9.9 kb, viewer]) giving information on the petrography, thickness, genesis, physical/chemical/structural characteristics, economic value, and water supply and quality for each rock polygon on the maps.